DDL vs DML vs DCL vs TCL
DDL: Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples:
* CREATE – to create objects in the database
* ALTER – alters the structure of the database
* DROP – delete objects from the database
* TRUNCATE – remove all records from a table, including all spaces allocated for the records are removed
* COMMENT – add comments to the data dictionary
* RENAME – rename an object
DML: Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples:
* SELECT – retrieve data from the a database
* INSERT – insert data into a table
* UPDATE – updates existing data within a table
* DELETE – deletes all records from a table, the space for the records remain
* MERGE – UPSERT operation (insert or update)
* CALL – call a PL/SQL or Java subprogram
* EXPLAIN PLAN – explain access path to data
* LOCK TABLE – control concurrency
DCL: Data Control Language (DCL) statements. Some examples:
* GRANT – gives user’s access privileges to database
* REVOKE – withdraw access privileges given with the GRANT command
TCL: Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.
* COMMIT – save work done
* SAVEPOINT – identify a point in a transaction to which you can later roll back
* ROLLBACK – restore database to original since the last COMMIT
* SET TRANSACTION – Change transaction options like isolation level and what rollback segment to use
DDL: Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples: * CREATE – to create objects in the database * ALTER – alters the structure of the database * DROP – delete objects from the database * TRUNCATE – remove all records from a table, including all spaces…
DDL vs DML vs DCL vs TCL
DDL: Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples:
* CREATE – to create objects in the database
* ALTER – alters the structure of the database
* DROP – delete objects from the database
* TRUNCATE – remove all records from a table, including all spaces allocated for the records are removed
* COMMENT – add comments to the data dictionary
* RENAME – rename an object
DML: Data Manipulation Language (DML) statements are used for managing data within schema objects. Some examples:
* SELECT – retrieve data from the a database
* INSERT – insert data into a table
* UPDATE – updates existing data within a table
* DELETE – deletes all records from a table, the space for the records remain
* MERGE – UPSERT operation (insert or update)
* CALL – call a PL/SQL or Java subprogram
* EXPLAIN PLAN – explain access path to data
* LOCK TABLE – control concurrency
DCL: Data Control Language (DCL) statements. Some examples:
* GRANT – gives user’s access privileges to database
* REVOKE – withdraw access privileges given with the GRANT command
TCL: Transaction Control (TCL) statements are used to manage the changes made by DML statements. It allows statements to be grouped together into logical transactions.
* COMMIT – save work done
* SAVEPOINT – identify a point in a transaction to which you can later roll back
* ROLLBACK – restore database to original since the last COMMIT
* SET TRANSACTION – Change transaction options like isolation level and what rollback segment to use
DDL: Data Definition Language (DDL) statements are used to define the database structure or schema. Some examples: * CREATE – to create objects in the database * ALTER – alters the structure of the database * DROP – delete objects from the database * TRUNCATE – remove all records from a table, including all spaces…