About Transaction objects
In a PowerBuilder database connection, a Transaction
object is a special nonvisual object that functions
as the communications area between a PowerBuilder application and
the database. The Transaction object specifies the parameters that
PowerBuilder uses to connect to a database. You must establish the
Transaction object before you can access the database from your
application, as shown in Figure 12-1:
database
Communicating with the database
In order for a PowerBuilder application to display and manipulate
data, the application must communicate with the database in which
the data resides.
To communicate with the database from your PowerBuilder
application:
-
Assign the appropriate values to the Transaction
object. -
Connect to the database.
-
Assign the Transaction object to the DataWindow
control. -
Perform the database processing.
-
Disconnect from the database.
For information about setting the Transaction
object for a DataWindow control and using the DataWindow to retrieve
and update data, see the DataWindow Programmer’s
Guide
.
Default Transaction object
When you start executing an application, PowerBuilder creates
a global default Transaction object named SQLCA (SQL Communications Area). You can
use this default Transaction object in your application or define
additional Transaction objects if your application has multiple
database connections.
Transaction object properties
Each Transaction object has 15 properties, of which:
- Ten are used to connect to
the database. - Five are used to receive status information from
the database about the success or failure of each database operation.
(These error-checking properties all begin with SQL.)
Description of Transaction object properties
Table 12-1 describes
each Transaction object property. For each of the ten connection
properties, it also lists the equivalent field in the Database Profile Setup
dialog box that you complete to create a database profile in the PowerBuilder
development environment.
Transaction object properties for your PowerBuilder
database interface For the Transaction object properties that
apply to your PowerBuilder database interface, see “Transaction object
properties and supported PowerBuilder database interfaces”.
For information about the values you should
supply for each connection property, see the section for your PowerBuilder
database interface in Connecting to Your Database
.
| Property | Datatype | Description | In a database profile |
|---|---|---|---|
| DBMS | String | The DBMS identifier for your connection. For a complete list of the identifiers for the supported database interfaces, see the online Help. |
DBMS |
| Database | String | The name of the database to which you are connecting. |
Database Name |
| UserID | String | The name or ID of the user who connects to the database. |
User ID |
| DBPass | String | The password used to connect to the database. | Password |
| Lock | String | For those DBMSs that support the use of lock values and isolation levels, the isolation level to use when you connect to the database. For information about the lock values you can set for your DBMS, see the description of the Lock DBParm parameter in the online Help. |
Isolation Level |
| LogID | String | The name or ID of the user who logs in to the database server. |
Login ID |
| LogPass | String | The password used to log in to the database server. |
Login Password |
| ServerName | String | The name of the server on which the database resides. |
Server Name |
| AutoCommit | Boolean | For those DBMSs that support it, specifies whether PowerBuilder issues SQL statements outside or inside the scope of a transaction. Values you can set are:
For more information, see the AutoCommit description |
AutoCommit Mode |
| DBParm | String | Contains DBMS-specific connection parameters that support particular DBMS features. For a description of each DBParm parameter that PowerBuilder supports, see the chapter on setting additional connection parameters in Connecting to Your Database . |
DBPARM |
| SQLReturnData | String | Contains DBMS-specific information. For example, after you connect to an Informix database and execute an embedded SQL INSERT statement, SQLReturnData contains the serial number of the inserted row. |
— |
| SQLCode | Long | The success or failure code of the most recent SQL operation. For details, see “Error handling after a SQL statement”. |
— |
| SQLNRows | Long | The number of rows affected by the most recent SQL operation. The database vendor supplies this number, so the meaning may be different for each DBMS. |
— |
| SQLDBCode | Long | The database vendor’s error code. For details, see “Error handling after a SQL statement”. |
— |
| SQLErrText | String | The text of the database vendor’s error message corresponding to the error code. For details, see “Error handling after a SQL statement”. |
— |
Transaction object properties and supported PowerBuilder database interfaces
The Transaction object properties required to connect to the
database are different for each PowerBuilder database interface.
Except for SQLReturnData,
the properties that return status information about the success or
failure of a SQL statement apply
to all PowerBuilder database interfaces.
Table 12-2 lists
each supported PowerBuilder database interface and the Transaction
object properties you can use with that interface.
| Database interface | Transaction object properties |
|
|---|---|---|
| Informix |
|
|
| JDBC |
|
|
| Microsoft SQL Server |
|
|
| ODBC |
|
|
| OLE DB |
|
|
| Oracle |
|
|
| Sybase DirectConnect |
|
|
| Sybase Adaptive Server Enterprise |
|
|
# UserID is optional for ODBC.
(Be careful specifying the UserID property; it overrides the connection’s
UserName property returned by the ODBC SQLGetInfo call.)
+ PowerBuilder uses the LogID
and LogPass properties only if your ODBC driver does not support
the SQL driver CONNECT call.