Document 6509645
Transcription
Document 6509645
Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Joseph Pescatello and Sarah Boucher For a Domino developer or administrator, invoking a procedure stored in a relational database from a Domino application can mean faster application performance, reduced network traffic, more efficient use of computing resources, and enhanced application functionality. Joe Pescatello IBM Software Developer IBM Lotus Workplace Messaging Most enterprise-level relational database systems1 allow a thirdparty application like Domino to invoke a procedure that encapsulates functionality like sorting, grouping, or performing calculations on stored data. The procedure can be written in any of several different programming languages2 and is compiled and stored in the relational database. When invoked by name, the procedure executes using any input values received from the invoking application; it can also return values. For instance, let’s say you have managers working in Notes/Domino who need salary data as they plan salaries and bonuses for employees. When reviewing an individual employee’s record in a document, a manager needs to know the current average salary for the company division in which that employee works. Your first thought might be to transfer the salary data for all employees in the division from the Human Resources RDBMS to Domino and make the calculation locally, but that involves sending a lot of data over your network. You can use network resources more efficiently and build faster performance into your application by enabling your application to invoke a procedure stored in the RDBMS. The stored procedure will receive a Sarah Boucher Enterprise Integration Manager IBM Lotus Software 1 DB2, Oracle, and Microsoft’s SQL Server, for example. 2 For example, the DB2 Stored Procedure Builder allows SQL (in version 7.1 or later), Java, C, COBOL, and C++. (complete bios appear on page 126) No portion of this publication may be reproduced without written consent. 103 THE VIEW November/December 2003 division or group parameter from your application; then it will calculate the average salary for that organization and pass the value back to Notes. Only one value — the current average — passes over the network to the Domino application. The result is only transferred when it has been requested by the invoking application, so you avoid overloading the network with data that the Domino application doesn’t need to use or display. Because the stored procedure is already compiled and optimized in the relational system, it executes more quickly than standard SQL queries. Another benefit is that you can make your stored procedure accessible to other third-party or SQL clients that access the RDBMS database, thus extending its value. Domino 6 provides broad support for stored procedures, allowing you to off-load large data-processing tasks to an enterprise database system and bring back the results.3 In this article, you’ll learn how to create stored procedures in a relational database and invoke them from your release 6 applications. We’ll concentrate on the basic mechanics of connecting a Domino 6 application to a DB2 stored procedure4 using three standard Domino integration tools — Domino Enterprise Connectivity Services (DECS), Lotus Enterprise Integrator (LEI), and Lotus Connector LotusScript Extensions (LC LSX). With a sample DB2 database, a couple of stored procedures, and a simple Domino application, we’ll show you how to use each of these tools to establish an activity that connects your application to a stored procedure and displays the output. The knowledge you gain will enable you to build faster, more efficient Domino applications. You’ll also 3 Prior to Domino 6, Lotus connectivity support for invoking stored procedures and receiving their outputs is not fully supported in all releases of Domino, nor is it supported in all releases of the Lotus integration tools. 4 Invoking stored procedures on other database systems like Oracle, Sybase, or Microsoft SQL Server is quite similar. If you are working with a relational database system other than DB2, you may only need to modify the SQL and stored procedure syntax in the examples. (Consult your RDBMS documentation or your database administrator for clarification.) If you are working in another type of enterprise environment (such as SAP R/3), you can still benefit from learning the principles of using stored procedures from Domino applications. 104 receive guidance on knowing when a stored procedure is appropriate for your application and how to troubleshoot problems with stored procedures. To get the most out of this article, you’ll need a working knowledge of Domino development; a basic understanding of DECS, LEI, and LC LSX; and familiarity with database administration and concepts. To create and run the demonstration exercises, you’ll need the following resources: • A release 6 Notes client, Domino Designer client, and Domino server • DECS or LEI release 6 • DB2 7.2 or 8.1 (on iSeries, DB2 V5R1, or V5R2) Let’s start by learning how to recognize when it’s appropriate to employ a stored procedure. When Should You Use a Stored Procedure? There are no hard and fast rules as to when to use stored procedures in Domino applications. Still, the following guidelines will help you identify opportunities to cut down network traffic, make better use of computing resources, and improve the overall performance of your application. This list is not exhaustive, but it should get you thinking about when to use stored procedures. ✓ Any application that uses multiple database records to compute a single value (such as calculating the average salary in a division) is a good candidate for a stored procedure. Let the database engine churn through its records, perform the calculation, and return the desired value. You won’t increase network traffic, and the database system will almost certainly perform the computation faster than Domino. ✓ Similarly, any application that compares, sorts, or groups database records together is a good candidate for a stored procedure. Do you want to compare inventory across warehouse locations? Or look at www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications sales revenue by region? To make the necessary calculations, stored procedures are a good choice. Now that you have some idea of when to use a stored procedure, let’s set up an environment for the examples. ✓ If more than one client requires a particular functionality, you should consider creating a stored procedure. For example, if your Domino application needs to perform the same calculation as your data warehouse, you can save time and maintenance headaches by coding the calculation function in a stored procedure. However, make sure you consider the caveats discussed next. The Caveats While a stored procedure can bring a great many benefits, we recommend employing one only after careful consideration. There are a few potential pitfalls, though you can avoid them easily with some forethought: • • • If more than one application depends on a stored procedure, make sure that the requirements of each are compatible. If one application’s requirements change, you may have to decouple the altered application and write a new procedure for it. If your database team has already written a stored procedure with the functionality you need to expose in a Domino application, consider using it. If your requirements match those of the procedure owner, you may be able to take advantage of the existing code. Just be aware that if you use someone else’s stored procedure, you will be at his or her mercy. As in the caveat above, make sure your requirements match those of the procedure owner. Many database administrators and managers wisely restrict programmers’ ability to write SQL queries against the enterprise data store. Inefficient SQL can bring a system to its knees and can have devastating effects on the performance of any applications that access the system. If your organization demands it, you must rely on your database programmers to write the stored procedures you want to call from Domino applications. No portion of this publication may be reproduced without written consent. Setting Up the Examples All of the examples in this article illustrate how stored procedures can alter data available in your Domino applications without changing any data in the RDBMS system. We designed three examples to highlight each of the basic Lotus integration technologies — DECS, LC LSX, and LEI. (The sidebar on page 108 provides an overview of these three tools.) Each Domino integration tool satisfies the requirements of a different solution. All examples involve the use of a stored procedure that calculates the bonus for any employee in a sample DB2 database; some involve the use of an additional procedure as well. Any Domino 6 developer with proper authority to use a DB2 database should be able to execute all of the examples. Note! If you already have LEI, don’t skip the DECS example — if you do, you’ll have to manually create documents to use in the later examples. We’ll tell you how to implement the DECS example using LEI. If you don’t have LEI, the sidebar on page 109 tells you how to obtain a sample copy to use in the LEI example. Since the procedure to calculate an employee’s bonus is used in all three examples, we’ll show you how to create it now, along with the sample DB2 database and a simple Domino application that will call our stored procedures. We’ll start with the DB2 database. The Example DB2 Database The example stored procedures will operate on DB2 records of employee data from a table called “EMPLOYEES.” On your DB2 system, create a table 105 THE VIEW November/December 2003 with this name, using the SQL structure listed in Figure 1. Note! We named our DB2 database DB2SAMPLE. In all of our examples, the DB2 owner name is JPESCATE. You should use the owner name that’s appropriate for your system. Use the code shown in Figure 2 to populate the EMPLOYEES table with some dummy records for testing. (Be sure to change the owner name.) The Stored Procedure for Calculating a Bonus Our first procedure, CALCBONUS (to calculate a bonus), will take one input parameter that uniquely identifies the employee (EMPNO) whose bonus the end user (you, when testing the examples) wants to determine. In the examples, this stored procedure will calculate the bonus but will not write the value to a DB2 database table, as is usually done. Figure 1 Figure 3 contains the SQL code to create the CALCBONUS procedure on your DB2 server. (Be sure to check the DB2 documentation to make sure your DB2 server has the necessary environment for creating stored procedures.) To build a stored procedure, the first thing we do is issue the CREATE statement with the owner name (JPESCATE in the sample code) pre-pended to the procedure name, which in this case is CALCBONUS. Next, we define the input and output parameters. The input parameter has the same data type and size as the EMPNO column in the EMPLOYEES table; this will ensure that a parameter of an invalid type or size won’t make it through to the WHERE clause later in the procedure. The output parameters have the same data types and sizes as their associated columns in the EMPLOYEES table. These parameters will hold the values that get passed back to any program (DB2 or external) that calls the stored procedure — in our case, a sample Domino application. The DB2 “EMPLOYEES” Table CREATE TABLE JPESCATE.EMPLOYEES ("EMPNO" CHARACTER (10) UNIQUE NOT NULL , "LAST_NAME" VARCHAR (40) , "FIRST_NAME" VARCHAR (40) , "DIV_NAME" VARCHAR (50) , "SALARY" DECIMAL (9, 2) , "BONUS" DECIMAL (9, 2)) Figure 2 Sample Employee Records for the “EMPLOYEES” Table INSERT INTO JPESCATE.EMPLOYEES VALUES('1','SMITH','MARY','WESTERN', 45000.00,1000.00) INSERT INTO JPESCATE.EMPLOYEES VALUES('2','JOHNSON','JOHN','WESTERN', 65000.00,1000.00) INSERT INTO JPESCATE.EMPLOYEES VALUES('3','WILLIAMS','MARY','EASTERN', 100000.00,12000.00) INSERT INTO JPESCATE.EMPLOYEES VALUES('4','REDMAN','JUNE','WESTERN', 25000.00,1000.00) INSERT INTO JPESCATE.EMPLOYEES VALUES('5','PERRY','STEVE', 'EASTERN', 300000.00,1000.00) 106 www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications The SELECT statement calculates the 10% bonus (SALARY * .10) for the employee whose number (EMPNO) is passed as an input parameter and assigns the results of the calculation to the BONUS output parameter. Once the database engine digests and compiles a procedure, it stores the procedure as another piece of metadata5 in its database, similar to a DB2 table or view. You’ll see that Domino treats this stored procedure like any other type of metadata when you integrate it with your Domino application. 5 Metadata is a term used to describe the data, rules, constructs, and operations that exist in an enterprise system. Figure 3 The Sample Domino Application You’ll need to create a Domino 6 application to work with the DB2 data that you just created. The premise for the sample application is quite simple — you want to display some of the employee information from the DB2 table and the values calculated by the stored procedures. So, create a Domino database with a form called “Employee” that includes the fields shown in Figure 4. We called our application “Employee Example.” Set up a view in your application that displays the Employee form and has columns that show the form’s fields. SQL for the “CALCBONUS” Stored Procedure CREATE PROCEDURE JPESCATE.CALCBONUS (IN EMPNO CHARACTER(10), OUT LAST_NAME VARCHAR(40), OUT FIRST_NAME VARCHAR(40), OUT DIV_NAME VARCHAR (50), OUT SALARY DECIMAL (9,2), OUT BONUS DECIMAL (9,2)) LANGUAGE SQL P1: BEGIN DECLARE TEMP_EMPNO CHARACTER(10); SET TEMP_EMPNO=EMPNO; SELECT EMPNO, LAST_NAME, FIRST_NAME, DIV_NAME, SALARY, (SALARY*.10) INTO EMPNO, LAST_NAME, FIRST_NAME, DIV_NAME, SALARY, BONUS FROM JPESCATE.EMPLOYEES WHERE EMPNO=TEMP_EMPNO END P1 Figure 4 “Employee” Form Fields Notes Form Field Label Data Type Editable/Computed for Display EMPLOYEE NUMBER: Text Editable FIRST NAME: Text Editable LAST NAME: Text Editable DIVISION: Text Editable SALARY: Number Editable BONUS: Number Editable AVERAGE SALARY: Number Editable No portion of this publication may be reproduced without written consent. 107 THE VIEW November/December 2003 In the first example, you’ll see how shell documents are created automatically in this Domino database, one for each employee record now in the DB2 table you just created. When an employee document is opened, the current values from DB2 will be dropped into the editable fields (the data isn’t stored with the Domino database). When the CALCBONUS procedure runs from the Domino application, you’ll see the BONUS field filled with the result. (Subsequent examples will use another stored procedure to fill the AVERAGE SALARY field.) Now that you’ve completed the preliminary setup of the sample DB2 database, stored procedure, and Domino application, let’s go over the basic principles of establishing connections and using stored procedures. Connections, Activities, and Results The two basic components for connecting a Domino application to an external DBMS are the connection and the activity. The principles behind the two are integral to using stored procedures with Domino applications, no matter which integration tool you use. Establishing the Connection All of the Lotus integration tools used in this article connect to enterprise systems through the Lotus The Lotus Integration Tools Domino Enterprise Connectivity Services (DECS) DECS allows Notes/Domino users to view data from relational databases, ERP systems, and operatingsystem files as if it were Domino data. DECS works in real time, so when a user opens a document in Domino, DECS retrieves some or all of the data for that document from one or more records in one or more enterprise systems. DECS uses the same Lotus base connectors that the other standard Lotus integration tools use. (See the sidebar on page 110 for more on Lotus Connectors.) With DECS, you can build point-and-click activities that give users access to information in enterprise systems. When a user adds or changes a document in a DECS-enabled Domino database, DECS can insert or update the data in the backend. And when a user deletes a Domino document, DECS can delete the equivalent data from the backend. You can also use DECS to build applications that can invoke stored procedures and receive the results. You can use an interface called “DECS Administrator” to associate fields in one or more Domino forms with data in one or more enterprise systems for specific document events that take place in an application, such as Open or Delete. For a good introduction to DECS and how it works, visit http://media.lotus.com/appdev/decs/decs2.htm. 108 DECS has been a part of the Domino server since release 4.6.5; it installs as an option. To see if it’s running, issue a “show tasks” command at the Domino server console and look for DECS. If you don’t see it, consult the DECS Administrator Guide for installation instructions. Lotus Connectors LotusScript Extensions (LC LSX) Another option for accessing stored procedures in Domino applications is to use LotusScript agents. The Lotus scripting model enables developers to access and call procedures with more granularity and control than can be provided by a form-based activity such as DECS. Rather than calling a procedure with a document event like Open (as in this article’s first example), you can create a script to call a procedure exactly when and where you need it. LC LSX is a set of LotusScript extension classes that uses the standard Lotus connectors to open the Lotus scripting model to external data. (Again, see the sidebar on page 110 for more on Lotus Connectors.) The LC LSX engine is already part of both the Notes 6 client and the Domino 6 server — you don’t need to take any special steps to install it. One caveat about using an LC LSX script to access external data is that connectivity must be established www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Connectors that ship with the Domino server, LEI, and the Notes client. For the examples, we’ll use the Lotus Connector for DB2, one of the standard connectors that come with Domino 6. (For more on Lotus Connectors, see page 110.) In each integration tool, you create a connection specification to give Domino the information it needs to connect to an enterprise system. In LEI and DECS, the connection specification is a document; in an LC LSX agent, it’s part of the script. Note that DB2 connections always require, at a minimum, the database name, a database from the location where the script will run. Traditionally, the script runs from the Notes client if executed manually, as when invoked by a user clicking a button. If you use the Run on Server agent option or if you enable scheduling for your agent, the connectivity must be installed on the server where the agent executes. (See Domino Designer Help for more information about the Run on Server agent option.) You can find the online Lotus Connector LotusScript Extensions Guide at http://www-12.lotus.com/ldd/ doc/lei/6.0/lsxlc6.nsf. Lotus Enterprise Integrator (LEI) LEI 6 features a set of Data Management and Advanced RealTime* activities that provide a pointand-click interface for moving or synchronizing data between external data sources and Notes/Domino applications. It’s a continuation of the technology first introduced in Lotus NotesPump and is targeted to help you to execute high-volume data transfers or synchronizations without programming. Its centralized LEI Administrator is similar to the DECS * RealTime refers to DECS and LEI Virtual Field, Virtual Document, and Virtual Agent activities, in which data is drawn into a Notes form from an enterprise system in real time. No portion of this publication may be reproduced without written consent. user ID with the correct privileges for the actions required on the database (read, create, delete), and the password for accessing the database. For example, when creating a Domino connection of any sort to the CALCBONUS stored procedure, you’ll need to build in the DB2 name of the procedure (CALCBONUS), a valid user ID that gives the calling mechanism access to CALCBONUS, and the password (if required by the DB2 system). If any of these elements change, you’ll need to update all connection documents or scripts that connect to the procedure. Administrator in that you create, modify, and control the execution of your activities from one location. When you use LEI to create access to a stored procedure, you construct a Virtual Agent, Virtual Fields (as in DECS), or a Virtual Document, all components of LEI Advanced RealTime. The third example in this article shows you how to build a Virtual Agent into a Domino application; the method is the same as adding traditional agents. While DECS is available as a component of the Domino server, LEI is a separate product with advanced capabilities and is purchased separately. During installation, LEI converts DECS activity and connection documents to LEI versions. Once LEI is installed, only the LEI Administrator is available; it replaces the DECS Administrator. LEI 6 requires matching versions of the Domino 6 server and Notes 6 client for administering LEI connections and activities. If you do not already have LEI 6 installed, you can download a trial copy from the Lotus Developer Domain. (Visit http://www.lotus.com/ldd/products.nsf/products/ei and click on “Free Trials” in the Downloads section.) You can also obtain more information on LEI and its options at http://www.lotus.com/ei by selecting the “Lotus Enterprise Integration” product page. 109 THE VIEW November/December 2003 Establishing an Activity In the Lotus integration tools, an activity relates the information in the source database to some aspect of the Domino application. Using DECS, you can create an activity as a document that, upon a document event like Open or Create, sends or receives data in its form fields, or you can specify an activity with finer detail in a LotusScript agent (LC LSX) or a Virtual Agent (LEI). Output Parameters and Return Values In general, stored procedures can return values to applications by using output parameters or by declaring in their signature the type of data they return. When a stored procedure declares that it returns a data value, that value is called a “return value.” Lotus Connectors don’t currently support return values generated by stored procedures. However, DECS, LC LSX, and LEI support the return of output parameters, so you can accept into Domino any output parameter values that result from running a stored procedure. The Lotus connectors pass your input parameters when the stored procedure is called and pass back the output parameters when the procedure is executed, thus making the output values available to Domino applications. (See the Lotus Connector documentation for information regarding input- and outputparameter support for stored procedures on your enterprise system.) Those are the basics. Now it’s time to dive into our first example. Lotus Connectors Lotus supports native access to a wide variety of external data structures with a set of Lotus base connectors that use the standard Lotus Connector API. All Lotus base connectors work with all of the Domino integration tools. For each Lotus Connector, you must have the appropriate connectivity software installed on the machine where DECS or LEI is installed or at the location where LC LSX scripts will be executed. Some of the Lotus Connectors and the enterprise software versions that each supports are listed below. depending on the operating system where the DB2 server is located. On Windows, UNIX, or Linux systems, connectivity to DB2 Universal Database (UDB) versions 7.2 and 8.1 is supported, including Workgroup, Enterprise, and Personal Editions. On the iSeries, the Lotus Connector for DB2 supports DB2/400. Access to DB2/390 is supported when connecting to DB2 UDB for OS/390 Version 6, and DB2 for z/OS and OS/390 Version 7. The Lotus Connector for DB2 supports Connect Enterprise and Personal Editions of DB2 UDB. Note that a Lotus Connector may not give you access to all features of the native DBMS, such as stored procedures (not all native DBMSs allow full access to their stored procedures). For online documentation with full instructions on using the Lotus Connectors, refer to the Lotus Connector and Connectivity Guide at http://www-12.lotus.com/ldd/doc/lei/6.0.1a/ lccon6.nsf. Oracle DB2 The Lotus Connector for DB2 supports several versions of IBM’s DB2 Universal Database (UDB), 110 Lotus has connectors for Oracle server versions 7 and 8, as well as an ODBC connector that can be used to connect to any version of Oracle, including Oracle 9. The Lotus Connector for Oracle 7 requires Oracle server version 7.3.4 and SQL*Net client connectivity on the Domino server where the application will run. The Lotus Connector for Oracle 8 requires Oracle server version 8.05 or 8i, plus the matching version of the Oracle 8 client. The Lotus Connector for Oracle 8 supports the initial release of Oracle 9, but to date it has had no functionality added to cover www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Example 1 — Making the Connection in Real Time with DECS In this example, the objective is to display employee records in the Employee Example Domino application and to implement the activity that runs the CALCBONUS stored procedure. We encourage you to try this example because the other examples make use of the Domino documents this exercise generates. To execute this example, you’ll need access to the DECS Administrator (decsadm.nsf), a Domino application created during Domino setup.6 (The side6 DECS must be selected during the setup. updates of Oracle 9. To take full advantage of Oracle 9 functionality, we recommend using the Lotus Connector for ODBC. (Note: The ODBC connector does not support output parameters.) bar on page 108 has information that can help you find it.) If you use LEI instead of DECS, you can follow along using similar tabs in LEI Administrator. Be sure to start by selecting Virtual Fields under the Add Activity tab. A DECS connection document gives Domino the information it needs to connect to an enterprise system. A DECS activity document relates a connection defined in a connection document to a form in a Domino application; it also performs these tasks: • Specifies the data fields involved, mapping the fields in the form to corresponding fields in DB2 • Specifies what document event triggers the integration activity Microsoft SQL Server, and other data sources for which there is no native Lotus Connector (MySQL, etc.). The ODBC connector requires a configured ODBC data source for the system that you’ll access. Sybase SQL Server The Lotus Connector for Sybase supports Sybase SQL Server version 11.9.2 on Windows and 11.1.1 on Solaris and AIX. We recommend the Lotus Connector for ODBC for use with newer versions of Sybase SQL Server. Microsoft SQL Server The Lotus Connector for OLE DB supports Microsoft SQL Server 7, SQL Server 2000, and Microsoft Access 2000. For connecting to SQL Server, the Lotus Connector requires Microsoft Data Access Components (MDAC) 2.0 or higher; we recommend MDAC 2.5. ODBC Data Access The Lotus Connector for ODBC supports connectivity to DB2, Oracle, Sybase SQL Server, No portion of this publication may be reproduced without written consent. As of this writing, the ODBC connector does not support output parameters in stored procedures. The examples in this article that use output parameters should not be attempted when using the ODBC connector. Support for output parameters is planned for a future revision of the connector. Premium Connectors — SAP R/3, others IBM also provides some premium connectors, such as a connector to SAP R/3 that supports output parameters. In SAP, these output parameters are called output tables or export parameters of Remote Function Calls (RFCs) or BAPIs. While this connector works with DECS, LEI, and LC LSX, it is not included with these products and is an additional purchase. 111 THE VIEW November/December 2003 Your starting point for building DECS connections and activities is the DECS Administrator. Figure 5 shows a typical main screen, including a view of existing activities and a navigation bar. There are three basic procedures to follow when establishing a connection and activity with DECS: 1. Define the connection to the external system. 2. RealTime-enable your Domino application by defining a DECS activity for it. In the activity, choose the appropriate connection and the Domino application; map the data between the external system and the Domino application; select a trigger event; and select the stored procedure to run. 3. Start the activity. Let’s walk through each of these procedures as you add CALCBONUS to your sample application. Defining the DECS Connection to the External System Start by clicking Add Connection in the DECS Administrator. Select “Connect to DB2” as your connection type. Remember that to make the DB2 connection, you’ll need the name of the sample DB2 database, a Figure 5 112 valid database user name, and a password with the appropriate access. (We used the SAMPLE database and the user name db2admin in the completed Connectivity section shown in Figure 6.) If you’re not sure what database user name or password to include in the connection document, ask your DB2 administrator. You can leave the Selection Type radio button at the default (Table), since the DB2 data is in a table. There are other connection options to further refine or control data access, but they are not required in this example. Now that you have created a connection to your DB2 system, you’re ready to create a DECS activity that specifies a Domino application to use with the connection. Remember that to make the DB2 connection, you’ll need the name of the sample DB2 database, a valid database user name, and a password. If you’re not sure what to include in the connection document, ask your DB2 administrator. The DECS Administrator www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Figure 6 Creating a DECS Connection to DB2 Enabling the Domino Application — Creating an Activity Document Using DECS To create the DECS activity, follow these steps: 1. Select “Add Activity” from the DECS Administrator and name your new activity. The Add Activity button is in the navigation bar of the Activities view of your DECS Administrator. (Refer to Figure 5.) If you do not see this button, make sure that you are in the “Activities” view. A blank form called “Virtual Fields Activity” will appear, in which you can create your activity document. Specify a name for your activity under the Identification section. 2. Select your Domino application and form. Click on the browse button next to “Domino Application” in your Virtual Fields Activity form and find the Domino application that you No portion of this publication may be reproduced without written consent. A DECS connection document gives Domino the information it needs to connect to an enterprise system. A DECS activity document relates a connection defined in a connection document to a form in a Domino application. wish to associate with the DB2 connection (the Employee Example database you created earlier). This application must be on the same server where DECS resides. Select the form within the application that will be used by this activity (Employee form, in this case). 3. Select your Lotus Connection. Click the Browse button in the Lotus Connection section to select the DB2 connection document that will form the link between this activity and the target DB2 database. You will be presented 113 THE VIEW November/December 2003 with a dialog box to select the metadata available via that connection (see Figure 7). For this example, you’ll use the DB2 connection created earlier and specify the EMPLOYEES table. You can see the activity form completed to this point in Figure 8; we named it “Stored Procedure Example.” Completing the Activity — Mapping Fields, Selecting the Event, Specifying the Stored Procedure Now we need to map the fields between the Domino application and the DB2 table, select the document event to monitor for this activity, and specify a procedure to run when the event occurs. To map the fields in the activity, go to the Mapping area of the activity form and select a key field or fields that will uniquely associate each document in Domino with a table row (or record) in Figure 7 114 DB2. Then, map the fields in your Domino form to corresponding fields on your DB2 side. Because “EMPNO” is the input parameter that our procedure requires, it will also be our key field. Map the fields LAST_NAME, FIRST_NAME, DIV_NAME, SALARY, and BONUS on your Domino form to their corresponding entries on the DB2 side. All of these fields must be mapped because they are returned as output parameters from our sample procedure. Also, notice that the Domino field names must match the DB2 table’s column names. When you have completed your mapping, your activity form should look like one shown in Figure 9. Next, you must specify an action in the Domino application that will trigger the stored procedure in the DB2 system. Document events for the Employee form in Domino are the possible triggers for this activity. First, in the Events area of the Activity form, select the Event Options tab; then, select which events to monitor. You can see The LEI Administrator Dialog for Selecting Metadata in the DB2 Database www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Figure 8 The Virtual Fields Activity Form — “Stored Procedure Example” Figure 9 The Virtual Fields Activity Form — Mapping Fields DECS No portion of this publication may be reproduced without written consent. LEI 115 THE VIEW November/December 2003 in Figure 10 the four document event options this tab offers. Here is how DECS behaves when monitoring for each type of event: • A Create event will intercept any new document created in Domino and insert a new record into the external system. • An Open event will display enterprise data when a user opens a Domino document and will ignore any changes made to the data in Domino during the same session. • An Update event will take any changes entered into the Domino document and cascade them out to the external system. • A Delete event will simply remove the corresponding records for a deleted Domino document from the external system. You can select one event or any combination of events to monitor in the same activity. You specify the procedure you want to use as you define each event. In this example, we’ll work with a procedure on the Open event. (For more background on event Figure 10 116 monitoring with stored procedures, see the sidebar on page 121.) Click the Open tab and look at the options for entering formulas and procedures. Enter your stored procedure name (JPESCATE.CALCBONUS in our example) in the Stored Procedure field and press F9. Pressing the F9 key displays the parameters that are required by the stored procedure — in our example, CALCBONUS requires EMPNO (see Figure 10). Initializing Keys and Starting the Activity To make a DECS activity operational, the developer must do two things: 1) initialize the key fields to populate them in the Notes database, and 2) start the activity in DECS Administrator. To initialize the key field for the example, make sure you save the activity document to accept changes; then click once on the activity document in the Activity view of DECS Administrator and select “Initialize Keys” from the action bar. (If you are using LEI Virtual Fields, you will need to save and reopen your activity and click on the Initialize Selecting Events to Monitor — The Events Tab www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Keys button.) For each row in the table, DECS (or LEI Virtual Fields) now creates one new Domino document using the Employee form. Each of the Employee documents will have data in the EMPNO field (the key field you designated in the activity document). The other fields will remain empty. DECS draws the key-field data from each row in the table; since our example uses a DB2 table containing five records, DECS should create five documents in your Domino application. Okay, your Domino application should now be ready to show data returned from the stored procedure. DECS only brings data back from the enterprise system when the activity is running. If you don’t start the activity, the user won’t see any data populating the Domino documents generated for the activity during initialization, other than the values in the initialized key fields. To start the activity, select your activity from the Activities view in the DECS Administrator and click Start on the Action bar. Once you start the DECS activity, two things happen every time an end user opens an Employee document in your Domino application. First, the non-key fields in the document will become populated as DECS pulls information from the external system into your application. The end user doesn’t have to know (and probably does not care) that the data in the form is not native Domino data and that it resides in an external enterprise system. Second, the end user will see the value of BONUS populated with the results of the stored procedure for calculating 10% of the salary. To demonstrate that the procedure is simply calculating a value and passing it off to Domino without changing any existing data in DB2, stop the DECS activity (in DECS Administrator, open the activity and click Stop). Remove the stored procedure value from the Event Options/Open tab; then save and restart the activity. Now open an Employee document in the application. You’ll see the native value of BONUS (nil) in your Domino application. In other words, DB2 doesn’t have a value for BONUS, so the field is empty. No portion of this publication may be reproduced without written consent. Now you’ve seen how DECS can integrate realtime data access with stored procedures by linking Domino documents with rows of DB2 data. You’ve seen the basics of building a DECS-enabled activity — the steps are the same regardless of what type of data source you access. The major point to remember when using DECS with stored procedures is that the key fields you specify in your activity will be passed to the procedure as input parameters. Keep this in mind when designing your application, activities, and procedures. To make a DECS activity operational, the developer must initialize the key fields to populate them in the Notes database and start the activity in DECS Administrator. Example 2 — A Scripted Solution Using LC LSX In this example, we’ll show you how to use LC LSX to connect the Employee form in Domino to a new stored procedure. Remember the Average Salary field you created in the Employee form? We’re going to create a stored procedure for calculating the average salary of the employee’s division, so the manager (the hypothetical end user of the sample Domino application) can compare it with the employee’s current salary during the review process. This example demonstrates how you can use LotusScript and the Lotus Connector for DB2 to collect input values from a Domino document, pass them to an external procedure, and then fetch an output parameter from a procedure’s results. Using Scripts to Call Stored Procedures Our procedure will take one input parameter, DIV_NAME, that specifies the division for which we want to determine the average salary and one output parameter, AVERAGE, which we’ll use to pass the calculated value back to our Domino application. 117 THE VIEW November/December 2003 Figure 11 Stored Procedure for Calculating the Average Salary in a Division CREATE PROCEDURE JPESCATE.SALARYAVERAGE (IN DIV_NAME VARCHAR(50), OUT AVERAGE DECIMAL(9,2)) LANGUAGE SQL P1: BEGIN DECLARE TEMP_DIV VARCHAR(50); SET TEMP_DIV = DIV_NAME; SET AVERAGE = (SELECT AVG(SALARY) FROM JPESCATE.EMPLOYEES WHERE DIV_NAME = TEMP_DIV GROUP BY DIV_NAME); END P1 Create the SALARYAVERAGE stored procedure shown in Figure 11 in your sample DB2 database. Figure 12 “Compute Average Salary” Agent Properties Once you have the new DB2 procedure, you can alter the Employee form to use a script to call the procedure and accept the data. The script we’ll use creates an agent using the Lotus Connector for DB2 and performs the following tasks: • Establishes connection properties to DB2 • Connects to DB2 • Sets up properties to pass to DB2 • Fetches data from the Domino form • Passes data to DB2 • Invokes the procedure • Fetches the resulting output parameter from the procedure • Presents the value from the procedure to the user via a dialog box In the Domino database where you created your Employee form, select View > Design and open the Employee form in Designer. Create a new agent and call it “Compute Average Salary.” Leave the rest of the options at the default settings, as in Figure 12, 118 and close the dialog box. (Note that the Runtime default in release 6, “Action menu selection,” is equivalent to the release 5 default, “Manually from Action Menu.”) Now you have a shell in which you can create the LC LSX agent. www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Select “LotusScript” as the agent type and copy the script from Figure 13. The second line, Uselsx "*lsxlc" , identifies the agent as an LC LSX type. The script establishes a connection to the DB2 database, defines the fields and field lists for passing data Figure 13 to and from the stored procedure, and displays the results of the procedure in a message box. Be sure to change the connection and procedure options within the script to match your particular installation. Save your script and exit. LotusScript Code for the “Compute Average Salary” Agent Option Public Uselsx "*lsxlc" Sub Initialize Dim Con As New LCConnection ("db2") Dim workspace As New NotesUIWorkspace Dim uidoc As NotesUIDocument Dim DIVISION As String Set uidoc = workspace.currentdocument ' set properties to connect to your DB2 datasource Con.database = "SAMPLE" Con.Userid = "db2user" Con.Password = "password" ' now connect con.connect ' set the connection property to the stored procedure name con.owner="JPESCATE" Con.Procedure = "SALARYAVERAGE" 'give it the names of the output parameters used by the procedure Con.FieldNames = "AVERAGE" Dim Parms As New LCFieldList Dim Result As New LCFieldList Dim out As Double ' append the fields with input parameters to the fieldlist Set PARM1 = Parms.Append ("DIV_NAME", LCTYPE_TEXT) PARM1.text = uidoc.FieldGetText( "DIV_NAME" ) 'call your procedure out = Con.Call (Parms,1,Result) 'fetch the output value out = Con.Fetch (Result,1,1) 'output the average to a message box Msgbox "The average salary for the division is $" & Result.AVERAGE (0) End Sub No portion of this publication may be reproduced without written consent. 119 THE VIEW November/December 2003 Figure 14 Result of Running the “SALARYAVERAGE” Procedure in DB2 via the “Compute Average Salary” Agent Before executing the agent, be sure you have employee division data in your Employee form. If your DECS activity (or its LEI equivalent) is running, you can use the division data that it provides from the DB2 table. If you didn’t create the activity in the DECS example, you can still run this LC LSX example by manually creating documents with the Employee form in the Domino database. If you are creating your own records, be sure that the DIV_NAME field contains either EASTERN or WESTERN as values. the value produced by the stored procedure, and present it to you in a dialog box within the Domino application. Figure 14 shows a typical outcome. When you have some Employee documents, you can try running the agent. (Enable LotusScript debugging first if you want to see variables as they are populated.) Open one of your Employee documents and select Compute Average Salary from the Domino Actions menu. The agent will take the value of the DIV_NAME field in your Domino document, pass it to the SALARYAVERAGE procedure in DB2, fetch This simple example shows how you can use LotusScript to take advantage of pre-existing enterprise business logic in stored procedures from within your Domino applications. The end user isn’t aware of anything other than the normal experience of executing a Domino agent. In our next example, you’ll see another way to allow end users of Domino applications to seamlessly access stored procedures. 120 As long as the LotusScript agent runs from a location where connectivity to the external system is established, you can use the agent to call a stored procedure from a Notes client, a Web browser, or any of the clients that Domino supports. You can also schedule your LC LSX agents using the agent builder in Designer. www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications Example 3 — Using an LEI Virtual Agent Now we’ll show you how to call the SALARYAVERAGE procedure using an LEI Virtual Agent. You can run an LEI Virtual Agent from the Actions menu of a Domino application activity, just like the LC LSX agent in the previous example; however, creating LEI Virtual Agents does not require any Domino-side programming. An advantage of creating LEI Virtual agents is that instead of writing agent code, you simply select a Domino application, the connection document, and the stored procedures to call. To complete this exercise, you’ll need Lotus Enterprise Integrator 6.x installed on a Domino 6 server. If you don’t have LEI, the “Additional Resources” sidebar on page 126 tells how to get a demonstration copy that is adequate for this example. You’ll also need the SALARYAVERAGE stored procedure created in the last exercise (shown in Figure 11) and some Employee documents in your sample Domino application (populated from the first example or created manually). To start, open the LEI Administrator. The LEI Administrator, like the DECS Administrator, is a Domino application with the filename decsadm.nsf (the same as the filename for DECS Administrator). When you install LEI on your server, it automatically upgrades the DECS Administrator database, converting connections and activities to LEI versions. The steps to create a Virtual Agent are similar to those in the DECS example — create a connection document; create a Virtual Agent (the activity document); select the connection and stored procedure; start the activity. Let’s begin by making the DB2 connection. Event Monitoring with Stored Procedures DECS and LEI RealTime activities allow you to monitor different events that occur in a Domino database. The type of event you monitor determines how the Domino application interacts with stored procedures. Keep the following points in mind when designing your activities: Open Event Procedures Any field specified as a key in your activity will be passed to the procedure as an input parameter. Any fields designated as output parameters by the procedure must be mapped as data fields in your activity. This means that any parameters defined in your procedure must exist as fields in both your Domino form and the enterprise-database table you’re using in the activity. Create or Update Event Procedures Any field mapped in your activity (key fields as well as data fields) will be passed to the stored procedure as input parameters. The output parameters passed back from the procedure do not have to exist in the No portion of this publication may be reproduced without written consent. table used by the activity. For example, the table of employee data does not have to contain a Bonus field for the stored procedure in the first example to calculate the bonus and pass it to the Domino application. You must also have a field defined on your Domino form if you want to capture the output parameter value. The output parameter and Notes field do not have to be mapped in your general field mapping list in the LEI Virtual Agent activity document, but they must be selected in the “Stored Procedure Output Mapping” section of the DECS activity document or the LEI Virtual Agent or Virtual Field activity document. Delete Event Procedures If you are invoking a procedure on the Delete event, no document is available to capture any output parameters that would be defined by your procedure. By the time the procedure has been executed, the initiating data in your Domino application is gone. Any fields designated as key fields in your activity will be passed to the procedure as input parameters. 121 THE VIEW November/December 2003 Creating an LEI Connection Document Creating a Virtual Agent Document In the LEI Administrator, click Add Connection. Following the same procedure you used in the DECS example, create a connection document to your DB2 database. You’ll need to specify the DB2 database, user ID, and password in the document. To open the Virtual Agents form, click Add Activity in LEI Administrator and select Virtual Agents (see Figure 15), or click Virtual Agents from the Create menu. The tasks to create a Virtual Agent are similar to the ones you would use in DECS to establish an activity. You can refer to Figure 16 to see how the form should be configured as we go through the steps: If you used LEI in the first example, you can use the same connection document in this example. Once an LEI connection document is complete, you can use it repeatedly in multiple activities. Figure 15 122 1. Select a Domino application. Use the same application you created for the other examples (Employee Example). LEI Administrator — Creating a Virtual Agent www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications 2. Select a Lotus Connection. Use the connection you created for the EMPLOYEES table in DB2. 3. Select a Stored Procedure. LEI shows you the stored procedures by owner. To select the procedure: - Select the External Owner Name you used when creating the SALARYAVERAGE procedure. - Click the Agent Pattern List browse button and select the SALARYAVERAGE procedure. Figure 16 4. Select “Save Output Parameters”. Find it under the General Options tab. This LEI option enables your Domino form to capture the value of SALARYAVERAGE once it’s fetched from the procedure. (See Figure 16.) 5. Name, save, and close the agent. For this exercise, call the agent SALARY_AVERAGE. You may have noticed other activity options (such as scheduling and SQL logging) in the connection Virtual Agents Activity Form No portion of this publication may be reproduced without written consent. 123 THE VIEW November/December 2003 document. We won’t go into these in this article; see the LEI documentation for more details. No Manual Initializing You probably noticed that while you must select key fields for DECS Virtual Fields, you do not need to select key fields for LEI Virtual Agents. If the stored procedure requires input parameters, the Virtual Agent passes the correct input parameters from fields and inserts the results in the selected Domino document. If the stored procedure doesn’t require input parameters, the Virtual Agent acts against all documents in the view that is active at the time the Virtual Agent is invoked. So in our example, the Virtual Agent runs against the document you select because the SALARYAVERAGE procedure takes the DIV_NAME field as an input parameter. If our sample procedure did not require any input parameters, the Virtual Agent would run the procedure and insert the results in all documents in the active view. Troubleshooting When an application misbehaves, it’s imperative to isolate the problem before trying to fix it. Troubleshooting a Domino application that’s linked to a system that is using stored procedures is an order of magnitude more difficult than working through a bug in a stand-alone application. You must determine if the problem is coming from the stored procedure, the enterprise system, or the Domino application. Depending on the complexity of each of these levels, the debugging experience can be a frustrating process. Fortunately, the nature of the symptom can sometimes point you towards the area where the problem lies. The following guidelines can help you start the debugging process. If a Domino application that uses a stored procedure runs but the results are wrong: • Make sure the LEI or DECS activity is running. This is tantamount to making sure your PC is plugged in when it won’t power up, so it should be the first thing you check. • Use the Domino Designer debugger to step through LC LSX code. Make sure the fields and parameters you’re sending and retrieving are correct. • Test the stored procedure outside of the Domino application. Use SQL or a tool like Computer Associates’ CleverPath Forest & Trees to make sure the stored procedure is doing what you expect it to do. • Look at the enterprise data against which the stored procedure is run. If the underlying data is bad, no amount of massaging will make it better. Any SQL tool will allow you to examine the data without invoking the stored procedure. Since developers don’t have to select key fields, Virtual Agents do not require a key initialization task. Starting the Virtual Agent Activity Once you’ve saved and closed the Virtual Agent, you need to start it for end users. To start the agent from LEI Administrator, select the activity document and click the Start button. Note that if your activities are set to autostart, you don’t need to restart them if the Domino application server goes down. After you’ve started your Virtual Agents Activity from LEI, end users can invoke it to run from the sample Domino application as they would any Domino agent. Test the agent by selecting an Employee document in your Domino application and then selecting the SALARY_AVERAGE agent from the Actions menu. Clicking the Virtual Agent’s name executes the stored procedure on the DB2 server and populates the Average field in your open document. If this example (or either of the others) didn’t work as expected, the suggestions in the next section may help. 124 If the application doesn’t run at all: • Again, make sure that the LEI or DECS activity is running and the Domino server on which the application lives is up and running. • Make sure that the back-end system is running and in good order. www.eVIEW.com ©2003 THE VIEW. All rights reserved. Let Your Relational Database Do the Work — How to Invoke Stored Procedures from Domino 6 Applications • • Check any error messages for signs that the problem is local to Domino or may be coming from the backend. If you see anything with a SQLState or SQL error, there’s a good chance that the problem is with the enterprise system, not Domino. If the errors are of the familiar Domino ilk, it’s possible (but not certain) that the problem is local. Domino treats data from stored procedures in a manner similar to native data, so the fact that you receive a Domino error doesn’t mean the problem originates in Domino. Make sure the information in the connection document (user name, password, and so on) is correct. If you can’t connect to the external database, the Domino application will not behave. Other Options for Optimizing Performance and Security Any time you start to write SQL (or other) code that touches an enterprise system, you introduce the potential for performance hits and security breaches. You have several built-in options to address these concerns, depending on which type of connection tool you are using. We’ll introduce you to the most frequently used ones here. Performance For better application performance, you’ll want to ensure that the fields you have specified as keys in your DECS or LEI activities or as input parameters for your LC LSX scripts are indexed in the DBMS database for faster access. As in our examples, the less time it takes DB2 to find the records and values it needs to execute your stored procedures, the greater the performance gain on your application. Indexing database records may require assistance from your DBAs. If so, provide them with the name of the table and key fields used in the activity. If you’re using an LC LSX agent to call a stored procedure, it could be a bit tricky to determine which table and fields need to be indexed. Unlike DECS and LEI, there is no LC LSX Administrator in which to map them; with LC LSX, you’ll need to have a No portion of this publication may be reproduced without written consent. good understanding of what input fields the stored procedure requires. Depending upon the composition of your procedure, any table being referenced by an activity or script should be indexed according to the input parameters requested by the procedure. Again, your DBA should be able to provide you with assistance. In RealTime activities, another way to optimize performance is with the Max Connections field on the forms for the Virtual Field (DECS and LEI) and Virtual Agent (LEI) activities. (You can see this field in Figures 9 and 16.) In both cases, the value of this field controls how many concurrent users can create, open, update, or delete records simultaneously. Lotus and other systems refer to the concept underlying Max Connections as “parallel persistent connections.” The system makes a connection to the database for each user for each event and then releases the connection back into the pool of available connections as soon as processing is completed. If more than one user requires a connection, or more than one event is triggered at the same time, an additional connection is created, used, and then released back into the pool. As more concurrent users or events require access, the system creates these connections until the value specified in Max Connections is reached. After that, DECS or LEI 6 queues user requests and executes them as connections become available. For example, say a user is accessing an application with a Virtual Agent that calls a procedure in DB2 that updates a record in a Domino application. When the user invokes the agent by clicking an Update button or selecting it from the Domino Action menu, LEI makes a connection to DB2 and calls the stored procedure; the stored procedure executes; and the LEI agent then displays the results in the Domino form. As soon as the action completes, LEI releases the connection and the system makes it available for others to use. Most applications are efficient with two (the default) or three parallel connections, depending upon the number of users accessing the particular agent and how long it takes the agent to complete. If users experience significant delays when invoking or executing the agent, try increasing the number of maximum connections in the corresponding activity document. 125 THE VIEW November/December 2003 Additional Resources Lotus EI For documentation on Lotus Enterprise Integration products, go to the Lotus Developer Domain Documentation Library at, http://www-10.lotus.com/ ldd/notesua.nsf. Click the by product link and select from the following: • Domino Enterprise Connection Services (DECS) • Enterprise Integrator (LEI) — We recommend that you look at Installation of LEI and configuration information for Connections and Activities • Lotus Connectors LotusScript Extensions Guide (LC LSX) Security When you set up Virtual Field or Virtual Agent activities that use a DBMS, you specify one DBMS user name and password. Every user calling your Virtual Agent or working with RealTime-enabled documents uses these DBMS credentials. DBMS administrators are understandably wary if the DBMS user specified in the activity’s connection document has global rights, however. To enhance security, LEI 6 allows you to have application users use their own credentials against the enterprise system, rather than those specified in the connection document. This functionality, called “Integrated Credentials,” adds another layer of security on top of the traditional Domino security model. You can find more information on this new functionality in the “LEI Activities and User Guide.” Conclusion With release 6 integration tools, using stored procedures from Domino applications is easy and can vastly increase your effectiveness and range as a developer. By using stored procedures to harness the power of your enterprise-database engine, you can reduce network traffic, enhance functionality, and improve performance 126 For IBM’s Lotus Enterprise Integration pages, including spec sheets, free downloads, success stories, and a discussion forum, visit http://www.lotus.com/ei. Another source of information is the developerWorks Product Pages for Lotus Enterprise Integration at http://www-10.lotus.com/ldd/products.nsf/products/ei. These pages list technical information, downloads, forums, white papers, and articles on the full suite of Enterprise Integration products. IBM DB2 The IBM DB2 Universal Database Web site, http://www-3.ibm.com/software/data/db2/udb/, provides technical information, documentation, downloads, services, and support information for IBM DB2. in your Domino applications. We look forward to hearing what you do with stored procedures in your release 6 applications. Joe Pescatello is an IBM software developer currently working on IBM Lotus Workplace Messaging. Joe has more than 15 years of experience in the industry. His areas of expertise include Java, portlet development, and database technologies. In addition to publishing technical articles in a variety of publications, he has delivered technical presentations in the US and across Europe on LEI 6, DECS, and stored procedures. Joe has filed four patents in the area of portlet development and computer security for IBM. Sarah Boucher manages the Enterprise Integration team for IBM in the Lotus Software division. She recently published an e-Pro Magazine article on Advanced RealTime in LEI 6. Sarah has also delivered presentations at LotusSphere on using external data and business logic to make Domino applications more powerful. You can reach her at [email protected]. www.eVIEW.com ©2003 THE VIEW. All rights reserved.