PROCEDURE CREATE_UPDATE_TRIGGER(ATable VARCHAR(31)) RETURNS (SQL_TEXT BLOB SUB_TYPE TEXT)
  AS
    DECLARE EOL CHAR(2);
    DECLARE PK_FIELDNAME VARCHAR(31);
  BEGIN
    ATable = TRIM(ATable);
    SELECT
      TRIM(IND.RDB$FIELD_NAME) AS FIELD_NAME
    FROM RDB$RELATION_CONSTRAINTS RC
      JOIN RDB$INDEX_SEGMENTS IND ON IND.RDB$INDEX_NAME = RC.RDB$INDEX_NAME
    WHERE RC.RDB$RELATION_NAME = :ATable AND RC.RDB$CONSTRAINT_TYPE = 'PRIMARY KEY'
    INTO PK_FIELDNAME;

    EOL = ASCII_CHAR(13) || ASCII_CHAR(10);
    SQL_TEXT = 'CREATE OR ALTER TRIGGER TR_' || ATable || '_REPL_AU FOR ' || ATable || EOL;
    SQL_TEXT = SQL_TEXT || 'ACTIVE AFTER UPDATE POSITION 0' || EOL;
    SQL_TEXT = SQL_TEXT || 'AS' || EOL;
    SQL_TEXT = SQL_TEXT || '  DECLARE LOG_ID INT;' || EOL;
    SQL_TEXT = SQL_TEXT || 'BEGIN' || EOL;

    SQL_TEXT = SQL_TEXT || '  EXECUTE PROCEDURE REPL_WRITE_LOG.BEGIN_OPERATION(' || '''' || ATable || ''', ''U'', ''' || PK_FIELDNAME || ''', OLD.' || PK_FIELDNAME || ') RETURNING_VALUES LOG_ID;' || EOL;
    FOR
      SELECT
           F.FIELD_SOURCE AS FIELD_NAME,
           F.FIELD_TYPE,
           F.FIELD_SCALE,
           F.FIELD_POS
      FROM
          TABLE_MAP T
          JOIN FIELD_MAP F ON F.CODE_TABLE_MAP = T.CODE_TABLE_MAP
      WHERE T.CODE_SENDER = 1 AND T.TABLE_SOURCE = :ATable
      ORDER BY F.FIELD_POS
      AS CURSOR C
    DO
    BEGIN
      SQL_TEXT = SQL_TEXT || '  IF (NEW.' || C.FIELD_NAME || ' IS DISTINCT FROM OLD.' || C.FIELD_NAME || ') THEN' || EOL;
      SQL_TEXT = SQL_TEXT || '    EXECUTE PROCEDURE REPL_WRITE_LOG.WRITE_' || C.FIELD_TYPE ||'_VALUE(LOG_ID, ''' || C.FIELD_NAME || ''', NEW.' || C.FIELD_NAME || ');' || EOL;
    END
    SQL_TEXT = SQL_TEXT || 'END' || EOL;
    SUSPEND;
  END