Bug #3252 Statement.getWarnings() not as specifiy in JDBC

• Submitted: 22 Mar 2004 0:39
• Modified: 22 Mar 2004 6:10
• Reporter: Klaus Halfmann
• Status: Not a Bug
• Category: Connector / J
• Severity: S3 (Non-critical)
• Version: mysql-connector-java-3.0.11-stable
• OS: Windows (WindowsXP)
• Assigned to: Mark Matthews
• CPU Architecture: Any

[22 Mar 2004 0:39] Klaus Halfmann

Description:
The JDBC API (jdk1.4.2/docs/api/java/sql/Statement.html#getWarnings()) says:

public SQLWarning getWarnings() throws SQLException

Retrieves the first warning reported by calls on this Statement object. 
Subsequent Statement object warnings will be chained to this SQLWarning object.

The code I decompile from the driver reads:
    
    public synchronized SQLWarning getWarnings() throws SQLException {
        return warningChain;
    }

but the warningChain is only set on 

   public synchronized void clearWarnings() throws SQLException {
        warningChain = pendingWarnings;
        pendingWarnings = null;
    }

Which is called before executing any statements.

So the code will only return warnings from the previous Statment.

How to repeat:
I dont know how to generate a warning with MySQL, yet,
so I cannot actually test this (pseudo) code, sorry.

Statement stm = connection.createStatement();
stm.execute("... <SQL WITH WARNINGS>...");
assertNotNull(stm.getWarnings());
stm.execute"... <SQL WITHOUT WARNINGS>...");
assertNull(stm.getWarnings());

Suggested fix:
The code above should work as expected.

[22 Mar 2004 6:10] Mark Matthews

The warning chain is never really set in Connector/J 3.0.x, because MySQL itself (at the point when Connector/J 3.0.x was feature frozen) did not support warnings. Therefore, the code was never completed.

Warning support is in Connector/J 3.1.x.