dataEvent_record_BeforeDeleteRow
Function called before deleting a row.
Syntax
PUBLIC FUNCTION dataEvent_record_BeforeDeleteRow(
uniqueKey record-type)
RETURNS (INTEGER, STRING, uniqueKey)
The function has this parameter:
uniqueKey
. This is aRECORD
type defined in the BAM-generated common file (my_entity_common.4gl). It includes the unique key fields from the schema of the database table.
- An integer with the
SQLCA.SQLCODE
error number. Codes are defined as constants in the libdbappSql and libdbappCore libraries. The errors that are relevant to this function are shown in Table 1.Table 1. SQLCA.SQLCODE Description Constant Value Success ERROR_SUCCESS
0 Failure ERROR_FAILURE
-1 - A string is returned with the
SQLERRMESSAGE
error message. uniqueKey
. This is aRECORD
type defined in the BAM-generated common file (my_entity_common.4gl). It includes the unique key fields from the schema of the database table.
Usage
When you select the Before Delete Row property for the creation of the event, a function shell is created. Enter your code in the function.
This function is called before deleting a row in the database. For example, you can use this function to write the row of data to a backup table before the row is deleted.
Example: BeforeDeleteRow
This example uses the Before Delete Row code event for the Account table in the OfficeStore demo.
In the example the row of data referenced by the variable uniqueKey
is written
to a backup table with a call to the function
writeDataToAccBackup
.
The writeDataToAccBackup
function
has a parameter that stores the row of data from the account table.
# AccountForm.4gl
-- import user-defined functions
IMPORT FGL myAccountFunc
PUBLIC FUNCTION dataEvent_recAccount_BeforeDeleteRow(uniqueKey recAccount_br_uk_type)
RETURNS (INTEGER, STRING, recAccount_br_uk_type)
DEFINE errNo INTEGER
DEFINE errMsg STRING
DEFINE l_data RECORD LIKE account.*
CALL libdbappCore.log(C_LOG_INFO, "dataEvent_recAccount_BeforeDeleteRow (Row scope) is raised")
SELECT * INTO l_data.* FROM account WHERE @userid = uniqueKey.account_userid
CALL myAccountFunc.writeDataToAccBackup(l_data) RETURNING errNo
IF errNo = libdbappCore.ERROR_FAILURE THEN
LET errMsg = " - BeforeDeleteRow failed to insert in backup "
END IF
CALL libdbappCore.log(C_LOG_INFO, "dataEvent_recAccount_BeforeDeleteRow (Row scope) is exited")
RETURN errNo, errMsg, uniqueKey.*
END FUNCTION
For more information on the libdbappCore.log()
function,
go to DBAPPDEBUG and the debug level API.
In this section there is an example of the function
writeDataToAccBackup
called to write data to a backup account
table. It is assumed that you have created the backup table for account before
saving the row to it.
All functions that you would reuse across forms and
applications would reside in a module you create. To use these functions in your
project, you would import your module into the entity module (for example,
AccountForm.4gl) using the IMPORT FGL
statement.
# MyAccountFunc.4gl
IMPORT FGL libdbappCore
FUNCTION writeDataToAccBackup(dataRec RECORD LIKE account.*)
RETURNS (INTEGER)
DEFINE errNo INTEGER
TRY
INSERT INTO account_backup VALUES (dataRec.*)
CATCH
DISPLAY "SQL ERROR: ", sqlca.sqlcode
LET errNo = libdbappCore.ERROR_FAILURE
END TRY
RETURN errNo
END FUNCTION