SQL/MX 3.2.1 Guide to Stored Procedures in Java (H06.26+, J06.15+)

SPJs in NonStop SQL/MX

This subsection explains the process and effect of registering and invoking SPJs in NonStop SQL/MX:

• Effect of Registering an SPJ (page 21)

• Effect of Invoking an SPJ (page 22)

• Invoking Different Types of SPJs (page 23)

Effect of Registering an SPJ

When you register an SPJ by using a CREATE PROCEDURE statement, NonStop SQL/MX verifies

that the specified Java method exists and that its signature matches the SQL parameters of the

stored procedure. After verifying the SPJ, NonStop SQL/MX stores information about the SPJ

method, such as its name, location, and parameter types, in the system metadata tables. After you

permissions can call the SPJ to execute the SPJ method.

Figure 2 shows how NonStop SQL/MX processes a CREATE PROCEDURE statement.

Figure 2 Registering an SPJ

1. The CREATE PROCEDURE statement that the application issues is processed by an SQL/MX

compiler (MXCMP) process.

2. The catalog manager within the MXCMP process invokes aninternal SPJ named VALIDAT

EROUTINE2, which is in SYSTEM_SQLJ_SCHEMA, and passes information from the CREATE

PROCEDURE statement to it.

3. VALIDATEROUTINE2 validates the Java class and method specified in the CREATE PROCEDURE

statement within an SQL/MX UDR server process (shown as the MXUDR executable in Figure 2).

VALIDATEROUTINE2 uses the embedded Java virtual machine (JVM) within the SQL/MX UDR

server process to verify that the Java method exists in the specified class and that its signature

maps to the SQL parameters specified in the CREATE PROCEDURE statement. If the method

exists and its signature maps to the SQL parameters, the SQL/MX UDR server returns a condition

indicating success to the MXCMP process. Otherwise, the SQL/MX UDR server returns an

error condition, and 4 do not complete.

SPJs in NonStop SQL/MX 21