SQL::ConnectionBeginTransaction Method

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Example
Note

Syntax

Result_Flag as L = BeginTransaction()

Returns

Result_FlagLogical: TRUE (.T.) if the operation was successful; otherwise FALSE (.F.).

Description

Begin a batch of SQL updates, inserts and/or deletes that need to succeed or fail as a group.

Discussion

The BeginTransaction() method begins a batch of SQL updates, inserts and/or deletes that need to succeed or fail as a group.

Example

First, create and define variables. The select_cmd will select the records to copy. The delete_cmd will select the records to delete.

dim conn as sql::connection
dim select_cmd as C
dim delete_cmd as C
select_cmd = "select * from ProductA"
delete_cmd = "delete * from ProductA"

Establish the connection. If there is an error, display a message, and end the script.

if .not.conn.open("{A5API=Access,FileName='C:\Program Files\A5V8\MDBFiles\Alphasports.mdb',UserName='Admin'}") then
    ui_msg_box("Error", "Could not establish connection" + crlf()+ conn.CallResult.text)
    end
end if

Select the data to copy. If there is an error, display a message, and end the script.

if .not. conn.execute(select_cmd) then
    ui_msg_box("Error", "Could not execute query" + crlf()+ conn.CallResult.text)
    end
end if

If the records were established, it is time to begin the transaction with the BeginTransaction() method.

conn.BeginTransaction()

Copy records from ProductA to ProductB. If there is an error, roll back the transaction with the RollBackTransaction() method, display a message, and end the script.

if .not. conn.InsertData("", "ProductB", conn.ResultSet)
    ui_msg_box("Error", "Could not insert data into ProductB")
    conn.RollBackTransaction()
    end
end if

Delete the records in ProductA. If there is an error, roll back the transaction, display a message, and end the script.

if .not. conn.execute(delete_cmd)
    ui_msg_box("Error", "Could not delete data from ProductA" + crlf()+ conn.CallResult.text)
    conn.RollBackTransaction()
    end
end if

Finally, commit the transaction and close the connection.

conn.CommitTransaction()
conn.close()

Note

Do not run conn.GetTableInfo() methods in the body of a transaction, as they execute their own transactions. You can run them before the transaction begins, or on a different connection.