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Result-Generating and Result-Free Statements

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SQL statements can be loosely divided into the following five categories:

  • Result Set-Generating Statements These are SQL statements that generate a result set. For example, a SELECT statement.

  • Row Count-Generating Statements These are SQL statements that generate a count of affected rows. For example, an UPDATE or DELETE statement.

  • Data Definition Language (DDL) Statements These are SQL statements that modify the structure of the database. For example, CREATE TABLE or DROP INDEX.

  • Context-Changing Statements These are SQL statements that change the context of a database. For example, the USE and SET statements in SQL Server.

  • Administrative Statements These are SQL statements used for administrative purposes in a database. For example, GRANT and REVOKE.

SQL statements in the first two categories are collectively known as result-generating statements. SQL statements in the latter three categories are collectively known as result-free statements. ODBC defines the semantics of batches that include only result-generating statements. These semantics vary widely and are therefore data source-specific. For example, the SQL Server driver does not support dropping an object and then referring to or re-creating the same object in the same batch. Therefore, the term batch as used in this manual refers only to batches of result-generating statements.