Selecting a data source
The data source you choose determines how you select the data
that will be used in the DataWindow object.
About the term data source The term data source used here refers
to how you use the DataWindow painter to specify the data to retrieve into
the DataWindow object. Data source can also refer to where the data comes
from, such as an Adaptive Server Anywhere data source (meaning a database file) or
an XML data source (meaning an XML file). Connecting to
Your Database
uses the term data source in this second
sense.
If the data is in the database
If the data for the DataWindow object will be retrieved from a database,
choose one of the following data sources:
| Data source | Use when |
|---|---|
| Quick Select | The data is from a single table (or from tables that are related through foreign keys) and you need only to choose columns, selection criteria, and sorting. |
| SQL Select | You want more control over the SQL SELECT statement generated for the data source or your data is from tables that are not connected through a key. For example, you need to specify grouping, computed columns, or retrieval arguments within the SQL SELECT statement. |
| Query | The data has been defined as a query. |
| Stored Procedure | The data is defined in a stored procedure. |
If the data is not in a database
Select the External data source if:
- The DataWindow object will be populated
programmatically. - Data will be imported from a DDE application.
- Data will be imported from an external file, such
as an XML, comma-separated values (CSV), tab-separated
text (TXT), or dBASE (DBF) file.
You can also use an ODBC driver to access data from a file. PowerBuilder includes
ODBC drivers for most file types.
For more information, see Connecting
to Your Database.
After you choose a data source in the various DataWindow wizards,
you specify the data. The data source you choose determines what
displays in the wizards and how you define the data.
Why use a DataWindow if the data is not from
a DBMS
Even when the data is not coming from the database, there
are many times when you want to take advantage of the intelligence
of a DataWindow object:
- Data Validation You have full access to validation rules for data
- Display Formats You can use any existing display formats to present the data,
or create your own - Edit Styles You can use any existing edit styles, such as radio buttons and
edit masks, to present the data, or create your own