You can access a wide variety of ODBC data sources in PowerBuilder. This section describes what you need to know to use ODBC connections to access your data in PowerBuilder.
The ODBC API
Open Database Connectivity (ODBC) is a standard application programming interface (API) developed by Microsoft. It allows a single application to access a variety of data sources for which ODBC-compliant drivers exist. The application uses Structured Query Language (SQL) as the standard data access language.
The ODBC API defines the following:
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A library of ODBC function calls that connect to the data source, execute SQL statements, and retrieve results
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A standard way to connect and log in to a DBMS
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SQL syntax based on the X/Open and SQL Access Group (SAG) CAE specification (1992)
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A standard representation for datatypes
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A standard set of error codes
Accessing ODBC data sources
Applications that provide an ODBC interface, like PowerBuilder, can access data sources for which an ODBC driver exists. An ODBC data source driver is a dynamic link library (DLL) that implements ODBC function calls. The application invokes the ODBC driver to access a particular data source.
Accessing Unicode data
Using the ODBC 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 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. 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.
What you can do
The following ODBC connectivity features are available in PowerBuilder:
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Connect to a SQL Anywhere standalone database (including the Demo Database) using the SQL Anywhere ODBC driver and the ODBC interface
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Create and delete local SQL Anywhere databases
For instructions, see the section called “Creating and deleting a SQL Anywhere database” in Users Guide.
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Connect to an installed SAP IQ database client through the ODBC interface.
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Use Level 1 or later ODBC-compliant drivers obtained from vendors other than SAP to access your data
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Use Microsoft's ODBC Data Source Administrator to define ODBC data sources
How an ODBC connection is made
When you access an ODBC data source in PowerBuilder, your connection goes through several layers before reaching the data source. 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 ODBC is a standard API, PowerBuilder uses the same interface to access every ODBC data source. As long as a driver is ODBC compliant, PowerBuilder can access it through the ODBC interface to the ODBC Driver Manager. The development environment and the ODBC interface work together as the application component.
The following figure shows the general components of an ODBC connection.
Figure: Components of an ODBC connection
Component descriptions
The following table gives the provider and a brief description of each ODBC component shown in the diagram.
|
Component |
Provider |
What it does |
|---|---|---|
|
Application |
SAP |
Calls ODBC functions to submit SQL statements, catalog requests, and retrieve results from a data source. PowerBuilder uses the same ODBC interface to access all ODBC data sources. |
|
ODBC Driver Manager |
Microsoft |
Installs, loads, and unloads drivers for an application. |
|
Driver |
Driver vendor |
Processes ODBC function calls, submits SQL requests to a particular data source, and returns results to an application. If necessary, translates an application's request so that it conforms to the SQL syntax supported by the back-end database. See Types of ODBC drivers. |
|
Data source |
DBMS or database vendor |
Stores and manages data for an application. Consists of the data to be accessed and its associated DBMS, operating system, and (if present) network software that accesses the DBMS. |
When PowerBuilder is connected to an ODBC data source, you might see messages from the ODBC driver that include the words single-tier or multiple-tier. These terms refer to the two types of drivers defined by the ODBC standard.
Single-tier driver
A single-tier ODBC driver processes both ODBC functions and SQL statements. In other words, a single-tier driver includes the data access software required to manage the data source file and catalog tables. An example of a single-tier ODBC driver is the Microsoft Access driver.
Figure: Single-tier ODBC driver
Multiple-tier driver
A multiple-tier ODBC driver processes ODBC functions, but sends SQL statements to the database engine for processing. Unlike the single-tier driver, a multiple-tier driver does not include the data access software required to manage the data directly.
An example of a multiple-tier ODBC driver is the SAP SQL Anywhere driver.
Figure: Multi-tier ODBC driver
You can access data in PowerBuilder with ODBC drivers obtained from vendors other than SAP, such as DBMS vendors.
An ODBC driver obtained from another vendor must meet certain conformance requirements to ensure that it works properly with PowerBuilder. This section describes how to make sure your driver meets these requirements.
PowerBuilder can access many data sources for which ODBC-compliant drivers exist. However, ODBC drivers manufactured by different vendors might vary widely in the functions they provide.
To ensure a standard level of compliance with the ODBC interface, and to provide a means by which application vendors can determine whether a specific driver provides the functions they need, ODBC defines conformance levels for drivers in two areas:
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API
Deals with supported ODBC function calls
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SQL grammar
Deals with supported SQL statements and SQL datatypes
API conformance levels
ODBC defines three API conformance levels, in order of increasing functionality:
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Core
A set of core API functions that corresponds to the functions in the ISO Call Level Interface (CLI) and X/Open CLI specification
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Level 1
Includes all Core API functions and several extended functions usually available in an OLTP relational DBMS
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Level 2
Includes all Core and Level 1 API functions and additional extended functions
To ensure the proper ODBC driver API conformance level:
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Appeon recommends that the ODBC drivers you use with PowerBuilder meet Level 1 or higher API conformance requirements. However, PowerBuilder might also work with drivers that meet Core level API conformance requirements.
SQL conformance levels
ODBC defines three SQL grammar conformance levels, in order of increasing functionality:
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Minimum
A set of SQL statements and datatypes that meets a basic level of ODBC conformance
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Core
Includes all Minimum SQL grammar and additional statements and datatypes that roughly correspond to the X/Open and SAG CAE specification (1992)
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Extended
Includes all Minimum and Core SQL grammar and an extended set of statements and datatypes that support common DBMS extensions to SQL
You can use the ODBC driver for the SQL Anywhere developer edition from SAP, provided with PowerBuilder, to access data. Other SAP database clients also include ODBC drivers that you can access through the PowerBuilder ODBC interface. See your database documentation for details.
PowerBuilder also let you access data with any Level 1 or higher ODBC-compliant drivers obtained from a vendor other than SAP. In most cases, these drivers will work with PowerBuilder.
Using existing Microsoft ODBC drivers
If you already have version 2.0 or later of any of the following Microsoft ODBC drivers installed and properly configured, you can use these drivers with PowerBuilder to connect to your data source:
| Microsoft Access (*.MDB) |
| Microsoft Btrieve (*.DDF) |
| Microsoft dBASE (*.DBF) |
| Microsoft Excel (*.XLS) |
| Microsoft FoxPro (*.DBF) |
| Microsoft Paradox (*.DB) |
| Microsoft Text (*.CSV, *.TXT) |
To ensure that you have up-to-date and accurate information about using your ODBC driver with PowerBuilder, get help as needed by doing one or more of the following:
|
To get help on |
Do this |
|---|---|
|
Using the ODBC Data Source Administrator |
Click the Help button on each tab. |
|
Completing the ODBC setup dialog box for your driver |
Click the Help button (if present) in the ODBC setup dialog box for your driver. |
|
Using SQL Anywhere |
See the SQL Anywhere documentation. |
|
Using an ODBC driver obtained from a vendor other than SAP |
See the vendor's documentation for that driver. |
|
Troubleshooting your ODBC connection |
Check for a technical document that describes how to connect to your ODBC data source. |
