You can create as many single- or multi-valued indexes for a database table as you need, and you can drop indexes that are no longer needed.
Update limitation
You can update a table in a form only if it has a unique index or primary key.
Creating an index
In SQL Anywhere databases
In SQL Anywhere databases, you should not define an index on a column that is defined as a foreign key, because foreign keys are already optimized for quick reference.
To create an index:
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Do one of the following:
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Highlight the table for which you want to create an index and click the Create Index drop-down toolbar button in PainterBar1.
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Select Object>Insert>Index from the main menu or New>Index from the pop-up menu.
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Expand the table's tree view, right-click on Indexes, and select New Index from the pop-up menu.
The Index's properties display in the Object Details view.
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Enter a name for the index in the Index box.
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Select whether or not to allow duplicate values for the index.
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Specify any other information required for your database.
For example, in Adaptive Server Enterprise specify whether the index is clustered, and in SQL Anywhere specify the order of the index.
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Click the names of the columns that make up the index.
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Select Save Changes from the pop-up menu.
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Right-click on the Object Details view and select Save Changes from the pop-up menu.
Any changes you made in the view are immediately saved to the table definition.
Modifying an index
You can modify an index.
To modify an index:
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Do one of the following:
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Highlight the index listed in the table's expanded tree view and click the Properties button.
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Select Properties from the Object or pop-up menu.
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Drag the index icon and drop it in the Object Details view.
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In the Object Details view, select or deselect columns as needed.
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Right-click on the Object Details view and select Save Changes from the pop-up menu.
Any changes you made in the view are immediately saved to the table definition.
Dropping an index
Dropping an index removes it from the database.
