IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

420 IMS Connectivity in an On Demand Environment: A Practical Guide to IMS Connectivity

Example 21-14 shows an example of SQL INSERT for a prepared statement.

Example 21-14 SQL INSERT statement for prepared statement

INSERT INTO CustomerDB.OrderTable(OrderNo, OrderName)

VALUES (?,?)

WHERE CustomerTable.CustomerNo = ?

Supported JDBC data types

IMS Java supports the JDBC data types listed in Table 21-2. The table also lists the

supported Java data types and how COBOL copybook types are mapped to it for JDBC type.

You can use several different Java methods to handle Java data types. For mapping

descriptions, see IMS Version 9: IMS Java Guide and Reference, SC18-7821.

Table 21-2 Supported JDBC data types

21.3 DLIModel utility

In order for a Java application to access an IMS database, it needs information about the

database. This information is contained in the PSBs and DBDs, but you must first convert this

information into a form that you can use in the Java application: a subclass of the

com.ibm.ims.db.DLIDatabaseView class called the

IMS Java metadata class. The DLIModel

utility generates this metadata from the IMS PSBs, DBDs, COBOL copybooks, and other

JDBC data type Java data type COBOL format

CHAR string PIC X

CLOB CLOB (supported only for IMS

XML database)

N/A

VARCHAR string PIC X

BIT Boolean N/A

TINYINT byte N/A

SMALLINT short From PIC 9(1) BINARY

To PIC 9(4) BINARY

INTEGER int From PIC 9(5) BINARY

To PIC 9(9) BINARY

BIGINT long From PIC 9(10) BINARY

To PIC 9(18) BINARY

FLOAT float COMP-1

DOUBLE double COMP-2

BINARY byte[] N/A

PACKEDDECIMAL java.math.BigDecimal PIC 9 COMP-3

ZONEDDECIMAL java.math.BigDecimal PIC 9 DISPLAY

DATE java.sql.Date N/A

TIME java.sql.Time N/A

TIMESTAMP java.sql.Timestamp N/A

Chapter 21. IMS Remote Database Services 421

input specified by utility control statements. In addition to creating the metadata class, this

utility also generates XML schemas of IMS databases. These schemas are used when

retrieving XML data from or storing XML data in IMS databases. In this section, we focus on

the metadata creation function of the DLIModel utility and provide a sample operation

procedure. For complete information about the DLIModel utility, see IMS Version 9: Utilities

Reference: System, SC18-7834.

Figure 21-7 shows the inputs and outputs from the DLIModel utility.

Figure 21-7 DLIModel utility inputs and outputs

The actions of the DLIModel utility are directed by control statements that you supply. The

control statements can specify:

 Which PSB to process during a run

 Aliases for the PSB, PCBs, segments, and fields

 Data types and format masks for fields

 XMI files that contain XMI descriptions of COBOL copybook members for segments

 Additional field definitions for fields that are not defined in the DBD or the COBOL

copybook XMI file

 Information that overrides PSB, DBD, and COBOL copybook XMI information

 Default values for newly inserted segments

The DLIModel utility reads the PSB and DBD source members from the partition data set

(PDS) or partition data set extended (PDSE) and parses them to build an in-memory model of

the database structure and the PSB view of that structure. The utility then generates the

outputs that were requested through control statements. You can specify an XMI description

of the entire in-memory model in which one description covers the PSB and all DBDs

processed in the run. You can also request a detailed trace file of the DLIModel utility

execution if such a trace is necessary for problem resolution.

After you create a metadata class from a PSB, you can install the metadata class as a

Datasource in WebSphere Application Server environment. The relationship between

metadata class and Datasource is mapped by Java Naming and Directory (JNDI) API. A Web

application in WebSphere Application Server for z/OS or distributed platforms will use JNDI to

make the specific ODBA connection to the IMS database manager.

PSB Source

(PDS)

DBD Source

(PDS)

COBOL XMI

(PDS or HFS)

Control

Statements

DLIModel

Utility

DLIModel

Java Report

(HFS)

Trace

(HFS)

XMI

(HFS)

MetaData

Class

(HFS)

DB Connection sample of Web Application

Context ctx = new InitialContext();

DataSource dds =

(DataSource)ctx.lookup(“java:comp/env/jdbc/CustomerDBView”);

Connection con = dds.getConnection();

J2C Connection

Factory Registration

(JNDI)