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The purpose of DQL commands is to get the schema relation based on the query passed to it. Although often considered part of DML, the SQL SELECT statement is strictly speaking an example of DQL. When adding FROM or WHERE data manipulators to the SELECT statement the statement is then considered part of the DML.
[2] [3] Non-autocommit mode enables grouping of multiple data manipulation SQL commands into a single atomic transaction. Some DBMS (e.g. MariaDB [4]) force autocommit for every DDL statement, even in non-autocommit mode. In this case, before each DDL statement, previous DML statements in transaction are autocommitted. Each DDL statement is ...
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).
A database trigger is like a stored procedure that Oracle Database invokes automatically whenever a specified event occurs. It is a named PL/SQL unit that is stored in the database and can be invoked repeatedly. Unlike a stored procedure, you can enable and disable a trigger, but you cannot explicitly invoke it.
A data control language (DCL) is a syntax similar to a computer programming language used to control access to data stored in a database (authorization). In particular, it is a component of Structured Query Language (SQL). Data Control Language is one of the logical group in SQL Commands.
SQL Plus internal commands, for example: environment control commands such as SET; environment monitoring commands such as SHOW; Comments; External commands prefixed by the ! char; Scripts can include all of these components. An Oracle programmer in the appropriately configured software environment can launch SQL Plus, for example, by entering:
Like Oracle's PL/SQL or Microsoft's Transact-SQL, DAL is essentially an extended version of SQL supporting basic query functionality and adding clean syntax for cursor operations, logic, and loops. When sent a command, early versions of Apple's DAL interpreter broke down the statement and re-built it into subqueries for the underlying data sources.
Example features R12: 1992: 24-hour processing, logical physical separation, catalog management, deadlock management, centralized security facility, SQL: R14: 1999-01-09 [5] Parallel sysplex exploitation, multitasking R15: 2001-04-25 [6] Improved performance, data sharing R16: 2004-04-13 [7] Two phase commit, TCP/IP, Parallel Access Volumes ...