Database Connection
Database
This is the reader dataset. When you enter the Database in the reader dataset field, it will be automatically added to this parameter.
Constraints
Tables
After specifying the database connection, click the Browse button (...) to select tables for import. A connection window appears while the system retrieves the tables from the database.
Once the Select Tables dialog appears, you can select one or more tables. Click OK to dismiss the window and add the selected table name(s) to the Tables parameter.
WHERE Clause
An SQL WHERE clause can be applied to the selected tables, to constrain the the row selection in tables chosen in the table list (for example, NUMLANES=2).
Schema Attributes
Additional Attributes to Expose
Use this parameter to expose Format Attributes in Workbench when you create a workspace:
- In a dynamic scenario, it means these attributes can be passed to the output dataset at runtime.
- In a non-dynamic scenario, this parameter allows you to expose additional attributes on multiple feature types. Click the browse button to view the available format attributes (which are different for each format) for the reader.
Advanced
Number Of Records To Fetch At A Time
The number of rows that are retrieved at one time into local memory from the data source. For example, if the value is set to 10000, the reader reads 10,000 rows into local memory, and processes features from this memory buffer. After the reading the last row, the reader retrieves the next 10,000 rows from the data source.
Note: If this parameter is incorrectly set, it will cause significantly degraded performance. The optimum value depends primarily on the characteristics of individual records and the transport between the database and the client machine. It is less affected by the quantity of rows that are to be retrieved. The optimal value is the default value set for the format (for example, 1 for PostGIS Raster, 10000 for PostGIS, or 10 for Microsoft SQL Server).