Connecting to Your Database
Using Oracle

The Oracle database interfaces support the Oracle datatypes listed in the following table in DataWindow objects and embedded SQL.

The ORA driver adds support for the XMLType datatype that was introduced with Oracle 9i. However, you cannot use this datatype with embedded SQL statements or in a DataWindow object.

Accessing Unicode data

PowerBuilder can connect, save, and retrieve data in both ANSI/DBCS and Unicode databases, but it does not convert data between Unicode and ANSI/DBCS. When character data or command text is sent to the database, PowerBuilder sends a Unicode string. The driver must guarantee that the data is saved as Unicode data correctly. When PowerBuilder retrieves character data, it assumes the data is Unicode.

A Unicode database is a database whose character set is set to a Unicode format, such as UTF-8, UTF-16, UCS-2, or UCS-4. All data must be in Unicode format, and any data saved to the database must be converted to Unicode data implicitly or explicitly.

A database that uses ANSI (or DBCS) as its character set might use special datatypes to store Unicode data. These datatypes are NCHAR and NVARCHAR2. Columns with this datatype can store only Unicode data. Any data saved into such a column must be converted to Unicode explicitly. This conversion must be handled by the database server or client.

A constant string is regarded as a char type by Oracle and its character set is NLS_CHARACTERSET. However, if the datatype in the database is NCHAR and its character set is NLS_NCHAR_CHARACTERSET, Oracle performs a conversion from NLS_CHARACTERSET to NLS_NCHAR_CHARACTERSET. This can cause loss of data. For example, if NLS_CHARACTERSET is WE8ISO8859P1 and NLS_NCHAR_CHARACTERSET is UTF8, when the Unicode data is mapped to WE8ISO8859P1, the Unicode data is corrupted.

If you want to access Unicode data using NCHAR and NVARCHAR2 columns or stored procedure parameters, use PowerBuilder variables to store the Unicode data in a script using embedded SQL to avoid using a constant string, and force PowerBuilder to bind the variables.

By default, the Oracle database interfaces bind all string data to internal variables as the Oracle CHAR datatype to avoid downgrading performance. To ensure that NCHAR and NVARCHAR2 columns are handled as such on the server, set the NCharBind database parameter to 1 to have the drivers bind string data as the Oracle NCHAR datatype.

For example, suppose table1 has a column c1 with the datatype NVARCHAR2. To insert Unicode data into the table, set DisableBind to 0, set NCharBind to 1, and use this syntax:

string var1
insert into table1 (c1) values(:var1);

If an Oracle stored procedure has an NCHAR or NVARCHAR2 input parameter and the input data is a Unicode string, set the BindSPInput database parameter to 1 to force the Oracle database to bind the input data. The Oracle database interfaces are able to describe the procedure to determine its parameters, therefore you do not need to set the NCharBind database parameter.

For a DataWindow object to access NCHAR and NVARCHAR2 columns and retrieve data correctly, set both DisableBind and StaticBind to 0. Setting StaticBind to 0 ensures that PowerBuilder gets an accurate datatype before retrieving.

TimeStamp datatype

The TimeStamp datatype in Oracle9i and later is an extension of the Date datatype. It stores the year, month, and day of the Date value plus hours, minutes, and seconds:

Timestamp[fractional_seconds_precision]

The fractional_seconds_precision value is optional and provides the number of digits for indicating seconds. The range of valid values for use with PowerBuilder is 0-6.