Handling SQL errors in an SQLj application

SQLj clauses use the JDBC class

 java.sql.SQLException

 for error handling. 

SQLj generates an SQLException under the following circumstances:

When any SQL statement returns a negative SQL error code 

When a SELECT INTO SQL statement returns a +100 SQL error code 

You can use the 

getErrorCode

 method to retrieve SQL error codes and the 

getSQLState

 method to retrieve SQLSTATEs.

To handle SQL errors in your SQLj application, import the 

java.sql.SQLException 

class, and use the Java error handling try/catch blocks to modify program flow 

when an SQL error occurs (see Example 7 51).

Example 7 51   SQL Exception with SQLj

try {

  #sql [ctxt] {SELECT LASTNAME INTO :empname

    FROM EMPLOYEE WHERE EMPNO= 000010 };

}

catch(SQLException e) {

  System.out.println("Error code returned: " + e.getErrorCode());

}

For exception handling in Java it is important to know that DB2 provides several 

types of JDBC drivers

with slightly different characteristics. With the DB2 

Universal JDBC Driver, you can retrieve the SQLCA. For the DB2 JDBC type 2 

driver for Linux, UNIX, and Windows (DB2 JDBC type 2 driver), use the standard 

SQLException to retrieve SQL error information.

SQLException under the DB2 Universal JDBC Driver

As in all Java programs, error handling is done using try/catch blocks. Methods 

throw exceptions when an error occurs, and the code in the catch block handles 

those exceptions.

JDBC provides the 

SQLException

 class for handling errors. All JDBC methods 

throw an instance of SQLException when an error occurs during their execution. 

According to the JDBC specification, an SQLException object contains the 

following information:

A string object that contains a description of the error or null 

A string object that contains the SQLSTATE or null 

An int value that contains an error code 

A pointer to the next SQLException or null 

The DB2 Universal JDBC Driver provides an extension to the SQLException 

class, which gives you more information about errors that occur when DB2 is 

216 

MySQL to DB2 UDB Conversion Guide