About the OLE DB interface
You can access a wide variety of data through OLE DB data
providers in PowerBuilder. This section describes what you need to
know to use OLE DB connections to access your data in PowerBuilder.
Supported OLE DB data providers For a complete list of the OLE DB data providers supplied
with PowerBuilder and the data they access, see “Supported
Database Interfaces” in online Help.
What is OLE DB?
OLE DB API
OLE DB is a standard application programming interface (API)
developed by Microsoft. It is a component of Microsoft’s
Data Access Components software. OLE DB allows an application to
access a variety of data for which OLE DB data providers exist.
It provides an application with uniform access to data stored in
diverse formats, such as indexed-sequential files like Btrieve, personal
databases like Paradox, productivity tools such as spreadsheets
and electronic mail, and SQL-based
DBMSs.
The OLE DB interface supports direct connections to SQL-based databases.
Accessing data through OLE DB
Applications like PowerBuilder that provide an OLE DB interface
can access data for which an OLE DB data provider exists. An OLE
DB data provider is a dynamic link library (DLL) that
implements OLE DB function calls to access a particular data source.
The PowerBuilder OLE DB interface can connect to any OLE DB
data provider that supports the OLE DB object interfaces listed
in Table 4-1. An OLE
DB data provider must support these interfaces in order to adhere
to the Microsoft OLE DB 2.0 specification.
| IAccessor | IDBInitialize |
| IColumnsInfo | IDBProperties |
| ICommand | IOpenRowset |
| ICommandProperties | IRowset |
| ICommandText | IRowsetInfo |
| IDBCreateCommand | IDBSchemaRowset |
| IDBCreateSession | ISourcesRowset |
In addition to the required OLE DB interfaces, PowerBuilder also
uses the OLE DB interfaces listed in Table 4-2 to provide further functionality.
| OLE DB interface | Use in PowerBuilder |
|---|---|
| ICommandPrepare | Preparing commands and retrieving column information. |
| IDBInfo | Querying the data provider for its properties. If this interface is not supported, database connections might fail. |
| IDBCommandWithParameters | Querying the data provider for parameters. |
| IErrorInfo | Providing error information. |
| IErrorRecords | Providing error information. |
| IIndexDefinition | Creating indexes for the extended attribute system tables. Also creating indexes in the Database painter. If this interface is not supported, PowerBuilder looks for index definition syntax in the pbodb100.ini file. |
| IMultipleResults | Providing information. |
| IRowsetChange | Populating the extended attribute system tables when they are created. Also, for updating blobs. |
| IRowsetUpdate | Creating the extended attribute system tables. |
| ISQLErrorInfo | Providing error information. |
| ISupportErrorInfo | Providing error information. |
| ITableDefinition | Creating the extended attribute system tables and also for creating tables in the Database painter. If this interface is not supported, the following behavior results:
|
| ITransactionLocal | Supporting transactions. If this interface is not supported, PowerBuilder defaults to AutoCommit mode. |
Accessing Unicode data
Using the OLE DB interface, PowerBuilder can connect, save,
and retrieve data in both ANSI/DBCS and Unicode databases
but 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 data provider 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. Columns with these
datatypes 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.
Components of an OLE DB connection
When you access an OLE DB data provider in PowerBuilder, your
connection goes through several layers before reaching the data
provider. It is important to understand that each layer represents
a separate component of the connection, and that each component
might come from a different vendor.
Because OLE DB is a standard API, PowerBuilder uses the same
interface to access every OLE DB data provider. As long as an OLE
DB data provider supports the object interfaces required by PowerBuilder, PowerBuilder can access
it through the OLE DB interface.
Figure 4-1 shows
the general components of a OLE DB connection.
Obtaining OLE DB data providers
There are two ways you can obtain OLE DB data providers for
use with PowerBuilder:
- From Sybase (recommended) Install the OLE DB data providers shipped with PowerBuilder.
You can do this either when you first install PowerBuilder or later. - From another vendor PowerBuilder Enterprise lets you access data with any OLE
DB data provider obtained from a vendor other than Sybase if that
data provider supports the OLE DB object interfaces required by PowerBuilder.
In most cases, these drivers work with PowerBuilder. However, Sybase
might not have tested the drivers to verify this. PowerBuilder Professional and Desktop editions The PowerBuilder Professional and Desktop editions do not support
the OLE DB interface.
Supported versions for OLE DB
The OLE DB interface uses a DLL named PBOLE100.DLL to
access a database through an OLE DB data provider.
Required OLE DB version To use the OLE DB interface to access an OLE DB database,
you must connect through an OLE DB data provider that supports OLE
DB version 2.0 or later. For information on OLE DB specifications,
see Microsoft’s Universal Data Access Web site
.