vtkSQLQuery

Section: Visualization Toolkit IO Classes

Usage

The abstract superclass of SQL query classes. Instances of subclasses of vtkSQLQuery are created using the GetQueryInstance() function in vtkSQLDatabase. To implement a query connection for a new database type, subclass both vtkSQLDatabase and vtkSQLQuery, and implement the required functions. For the query class, this involves the following:

Execute() - Execute the query on the database. No results need to be retrieved at this point, unless you are performing caching.

GetNumberOfFields() - After Execute() is performed, returns the number of fields in the query results.

GetFieldName() - The name of the field at an index.

GetFieldType() - The data type of the field at an index.

NextRow() - Advances the query results by one row, and returns whether there are more rows left in the query.

DataValue() - Extract a single data value from the current row.

Begin/Rollback/CommitTransaction() - These methods are optional but recommended if the database supports transactions.

.SECTION Thanks Thanks to Andrew Wilson from Sandia National Laboratories for his work on the database classes.

To create an instance of class vtkSQLQuery, simply invoke its constructor as follows

  obj = vtkSQLQuery

Methods

The class vtkSQLQuery has several methods that can be used. They are listed below. Note that the documentation is translated automatically from the VTK sources, and may not be completely intelligible. When in doubt, consult the VTK website. In the methods listed below, obj is an instance of the vtkSQLQuery class.