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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.
Suppose there is a simple database that lists people and addresses. More than one person can live at a particular address and a person can live at more than one address (this is an example of a many-to-many relationship). The database only has three tables, person, address, and pa, with the following data:
Common examples of DDL statements include CREATE, ALTER, and DROP. If you see a .ddl file, that means the file contains a statement to create a table. Oracle SQL Developer contains the ability to export from an ERD generated with Data Modeler to either a .sql file or a .ddl file.
SQL provides the functions CEILING and FLOOR to round numerical values. (Popular vendor specific functions are TRUNC (Informix, DB2, PostgreSQL, Oracle and MySQL) and ROUND (Informix, SQLite, Sybase, Oracle, PostgreSQL, Microsoft SQL Server and Mimer SQL.)) Temporal (datetime) DATE: for date values (e.g. 2011-05-03). TIME: for time values (e.g ...
In the examples below each trigger is modifying a different table, by looking at what is being modified you can see some common applications of when different trigger types are used. The following is an Oracle syntax example of a row level trigger that is called AFTER an update FOR EACH ROW affected.
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).
Though database systems use SQL, they also have their own additional proprietary extensions that are usually only used on their system. For Example Microsoft SQL server uses Transact-SQL (T-SQL) which is an extension of SQL. Similarly Oracle uses PL-SQL which is their proprietary extension for them only.
MySQL (/ ˌ m aɪ ˌ ɛ s ˌ k juː ˈ ɛ l /) [5] is an open-source relational database management system (RDBMS). [5] [6] Its name is a combination of "My", the name of co-founder Michael Widenius's daughter My, [7] and "SQL", the acronym for Structured Query Language.