SQLPreview event

Description

Occurs immediately before a SQL statement
is submitted to the DBMS. Methods that trigger DBMS activity are Retrieve, Update,
and ReselectRow.

PowerBuilder event information

Event ID: pbm_dwnsql

Argument	Description
request	SQLPreviewFunction by value. The function that initiated the database activity. For a list of valid values, see SQLPreviewFunction.
sqltype	SQLPreviewType by value. The type of SQL statement being sent to the DBMS. For a list of valid values, see SQLPreviewType .
sqlsyntax	String by value. The full text of the SQL statement.
buffer	DWBuffer by value. The buffer containing the row involved in the database activity. For a list of valid values, see DWBuffer.
row	Long by value. The number of the row involved in the database activity, that is, the row being updated, selected, inserted, or deleted.

Web ActiveX event information

Event name: beforeSQLPreview

Argument	Description
Request	Number. A number identifying the function that initiated the database activity. For a list of valid values, see SQLPreviewFunction.
SQLType	Number. A number identifying the type of SQL statement being sent to the DBMS. For a list of valid values, see SQLPreviewType .
SQLSyntax	String. The full text of the SQL statement.
dwBuffer	Number. A number identifying the buffer containing the row involved in the database activity. For a list of valid values, see DWBuffer.
Row	Number. The number of the row involved in the database activity—that is, the row being updated, selected, inserted, or deleted.

Return Values

Set the return code to affect the outcome of the event:

0 Continue processing
1 Stop processing
2 Skip this request and execute the next
request

For information on setting the return code in a particular
environment, see “About return values for
DataWindow events”.

Usage

Some uses for the sqlsyntax argument are:

Changing the SQL to be executed (you can get the
value of sqlsyntax, modify it, and call SetSQLPreview)
Keeping a record (you can write the SQL statement to a log file)

Reported row number

The row number stored in row is the number
of the row in the buffer, not the number the row had when it was
retrieved into the DataWindow object.

If the row that caused the error is in the Filter buffer,
you must unfilter it if you want the user to correct the problem.

GetSQLPreview and
binding

When binding is enabled for your database, the SQL returned in the GetSQLPreview method
may not be complete—the input arguments are not replaced
with the actual values. For example, when binding is enabled, GetSQLPreview might return
the following SQL statement:

INSERT INTO "cust_order" ( "ordnum", "custnum",

1	INSERT INTO "cust_order" ( "ordnum", "custnum",

"duedate", "balance" ) VALUES ( ?, ?, ?, ? )

1	"duedate", "balance" ) VALUES ( ?, ?, ?, ? )

When binding is disabled, it returns:

INSERT INTO "cust_order" ( "ordnum", "balance",

1	INSERT INTO "cust_order" ( "ordnum", "balance",

"duedate", "custnum" ) VALUES ( '12345', 900,

1	"duedate", "custnum" ) VALUES ( '12345', 900,

'3/1/94', '111' )

1	'3/1/94', '111' )

If you require the complete SQL statement
for logging purposes, you should disable binding in your DBMS.

For more information about binding, see Connecting
to Your Database.

Obsolete methods in PowerBuilder

Information formerly provided by GetSQLPreview and GetUpdateStatus is
available in the arguments sqlsyntax, row,
and buffer.

Examples

This statement in the SQLPreview event
sets the current SQL string
for the DataWindow dw_1:

dw_1.SetSQLPreview( &amp;

1	dw_1.SetSQLPreview( &

        "INSERT INTO billings VALUES(100, " + &amp;

1	"INSERT INTO billings VALUES(100, " + &

        String(Current_balance) + ")")

1	String(Current_balance) + ")")

SQLPreview – PB Docs 150

SQLPreview event

Description

Return Values

Usage

Examples

See Also

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