SQL/MX Programming Manual for Java

Introduction

HP NonStop SQL/MX Programming Manual for Java—523726-003

1-20

Executing an SQLJ Program

When you execute an SQLJ program, the program class file (for example,

MyProg.class) runs like any Java program except that it calls the SQLJ run time to

execute the embedded SQL/MX statements. The SQLJ run time connects to an

SQL/MX database by means of a JDBC connection.

When an SQLJ program executes, the JVM searches the directories and JAR files

specified by the class path and loads the classes necessary to run the application,

such as one or more JAR or class files for the application and the supporting JAR files

for the SQLJ run-time library (RTL), the JDBC/MX driver, and the Java library. When

the JVM encounters an SQL statement in the program class file, an SQLJ RTL routine

loads the extended profile. Information in the extended profile causes the SQLJ RTL to

make JDBC calls to load and execute the statement plan from the module.

Static SQLJ Execution

The SQLJ run time first tries to load each statically compiled SQL statement from the

module. This process is called the customized run time. Figure 1-4 shows the static

SQLJ execution environment.

Figure 1-4. Static SQLJ Execution Environment

VST003.vsd

JVM

JDBC/MX

MyProg

SQLJ Run Time

Keys File

MyProg_SJProfile

Keys.class

Iterator Class

MyProg$Iter.

class

Connection

Context Class

SQLMXCtx.class

Java Class File

of the SQLJ Program

MyProg.class

Extended Profile

MyProg_SJProfile0.ser

Module

CAT.SCH.GRP1^MOD1^

TABLESET1^VER1

/usr/tandem/sqlmx/USERMODULES