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MS SQL Server supports trigger for DML and DDL statement plus special trigger "logon". The scope of DDL triggers can be a database (CREATE TRIGGER name ON DATABASE ...) or the entire SQL Server instance (CREATE TRIGGER name ON ALL SERVER). When you use the entire instance, you can capture all events executed on commands that have server-level scop
Columnn, Now, NULL); END;-- Trigger for DELETE CREATE TRIGGER Database. TableDelete AFTER DELETE ON Database. OriginalTable REFERENCING OLD AS O FOR EACH ROW MODE DB2SQL BEGIN DECLARE Now TIMESTAMP; SET NOW = CURRENT TIMESTAMP; UPDATE Database. HistoryTable SET EndDate = Now WHERE Column1 = O. Column1 AND EndDate IS NULL; END;-- Trigger for ...
Programs calling a database that accords to the SQL standard receive an indication of the success or failure of the call. This return code - which is called SQLSTATE - consists of 5 bytes.
Queries can be nested so that the results of one query can be used in another query via a relational operator or aggregation function. A nested query is also known as a subquery . While joins and other table operations provide computationally superior (i.e. faster) alternatives in many cases, the use of subqueries introduces a hierarchy in ...
SQL was initially developed at IBM by Donald D. Chamberlin and Raymond F. Boyce after learning about the relational model from Edgar F. Codd [12] in the early 1970s. [13] This version, initially called SEQUEL (Structured English Query Language), was designed to manipulate and retrieve data stored in IBM's original quasirelational database management system, System R, which a group at IBM San ...
The mysqli_query(), mysqli_real_query() and mysqli_multi_query() functions are used to execute non-prepared statements. At the level of the MySQL Client Server Protocol, the command COM_QUERY and the text protocol are used for statement execution. With the text protocol, the MySQL server converts all data of a result sets into strings before ...
This pre-established query command is kept in the data dictionary. Unlike ordinary base tables in a relational database, a view does not form part of the physical schema: as a result set, it is a virtual table [1] computed or collated dynamically from data
Triggers are events triggered by the action of SQL data manipulation language (DML) statements. For example, an INSERT statement might activate a trigger that checks if the values of the statement are valid. Most triggers are only activated by either INSERT or UPDATE statements. Triggers are fully supported and can be attached to tables.