DB2 update trigger

I am trying to create a trigger in a DB2 database that runs on the update of a column in one table, and then fills in another table with certain values.

For example, there is a power unit table with a FLEET_ID column. Everytime the FLEET_ID is changed, I need to to create a new row in the TRANS_AUDIT table.

The TRANS_AUDIT schema is as follows:

CREATE TABLE LYNX.TRANS_AUDIT (
    TA_ID INTEGER NOT NULL,
    TA_KEY_VALUE VARCHAR(100),
    TA_TABLE_CHANGED VARCHAR(40),
    TA_FIELD_CHANGED VARCHAR(40),
    TA_OLD_FIELD_VALUE VARCHAR(100),
    TA_NEW_FIELD_VALUE VARCHAR(100),
    TA_USER_WHO_CHANGED VARCHAR(128),
    TA_DATE_CHANGED TIMESTAMP,
    TA_COMMENT VARCHAR(40),
    TA_OLD_FIELD_DOUBLE DOUBLE DEFAULT 0,
    TA_NEW_FIELD_DOUBLE DOUBLE DEFAULT 0,
    PRIMARY KEY (TA_ID)
);

Here is what I have so far, but I can't seem to get it to work, I am getting a function sequence error.

CREATE TRIGGER PU_UPD_FLEETID
AFTER UPDATE OF FLEET_ID ON PUNIT 
REFERENCING OLD AS O NEW AS N
FOR EACH ROW 
MODE DB2SQL 
BEGIN ATOMIC 

    DECLARE 
    vTA_ID INTEGER;

    IF(N.FLEET_ID <> O.FLEET_ID) THEN

        SELECT MAX(TA_ID)+1 FROM TRANS_AUDIT INTO vTA_ID; --generate a unique sequential id 
            INSERT INTO LYNX.TRANS_AUDIT (TA_ID, TA_KEY_VALUE, TA_TABLE_CHANGED, TA_FIELD_CHANGED, TA_OLD_FIELD_VALUE, TA_NEW_FIELD_VALUE, TA_USER_WHO_CHANGED, TA_DATE_CHANGED, TA_COMMENT, TA_OLD_FIELD_DOUBLE, TA_NEW_FIELD_DOUBLE)
            VALUES (TA_ID, N.UNIT_ID , 'PUNIT', 'FLEET_ID', O.FLEET_ID, N.FLEET_ID , SESSION_USER ,CURRENT TIMESTAMP , '', '0' ,'0' );
    END IF;
END;

In your INSERT statement, I believe the first entry in the VALUES should be vTA_ID, not TA_ID.

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