If only the <after> block is specified, the rows specified in the <after> block are inserted in the table(s). If both the <before> and <after> blocks are specified, then rows specified in the <after> block for which there are no corresponding rows in the <before> block are inserted in the table(s).

In an update operation, the rows specified in the <before> block refer to existing rows in the database. The corresponding rows in the <after> block reflect what the user wants in the database. A row update operation is performed if there is a row in both the <before> and <after> sections with the same set of values for the attributes that uniquely identify a row in a table. Rows specified in the <before> block must be valid in the database for the updategram to successfully update the rows.

In a delete operation, if only the <before> block is specified in the update gram, the rows specified in the <before> block are deleted from the table(s). If both the <before> and <after> blocks are specified, the rows for which there are no corresponding rows in the <after> block are deleted from the table(s).