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In SQL, the TRUNCATE TABLE statement is a data manipulation language (DML) [1] operation that deletes all rows of a table without causing a triggered action. The result of this operation quickly removes all data from a table , typically bypassing a number of integrity enforcing mechanisms.
The DROP statement is distinct from the DELETE and TRUNCATE statements, in that DELETE and TRUNCATE do not remove the table itself. For example, a DELETE statement might delete some (or all) data from a table while leaving the table itself in the database, whereas a DROP statement removes the entire table from the database.
The Data Definition Language (DDL) manages table and index structure. The most basic items of DDL are the CREATE , ALTER , RENAME , DROP and TRUNCATE statements: CREATE creates an object (a table, for example) in the database, e.g.:
Furthermore, I have been communicating about this with someone who has access to the ISO standard. He states: TRUNCATE is: - an "SQL-data change statement" - therefore an "SQL-data statement" It is not: - an "SQL-schema statement" The terms DDL and DML are not used in the SQL standard, but those above are pretty much the equivalents.
In Microsoft SQL Server there are four groups of SQL commands: [2] Data Manipulation Language (DML) Data Definition Language (DDL) Data Control Language (DCL) Transaction Control Language (TCL) DCL commands are used for access control and permission management for users in the database.
These sub-languages are mainly categorized into four categories: a data query language (DQL), a data definition language (DDL), a data control language (DCL), and a data manipulation language (DML). Sometimes a transaction control language (TCL) [ 1 ] is argued to be part of the sub-language set as well.
At a minimum, the SHOW statement should also be discussed. (2) Due in large part to a lack of standardization of DDL, most DMLs provide a DML interface that can be used as a DDL. A table showing correspondences between DDL and equivalent DML would be very useful. Vrmlguy 12:07, 7 January 2013 (UTC)
In SQL, the data manipulation language comprises the SQL-data change statements, [3] which modify stored data but not the schema or database objects. Manipulation of persistent database objects, e.g., tables or stored procedures, via the SQL schema statements, [3] rather than the data stored within them, is considered to be part of a separate data definition language (DDL).