Search results
Results from the WOW.Com Content Network
Sometimes databases also support alternative syntax for this; for example, MySQL allows omitting the DEFAULT keyword, and T-SQL can use DEFAULT VALUES instead of VALUES(DEFAULT). The DEFAULT keyword can also be used in normal insertion to explicitly fill a column using that column's default value:
For example: GRANT can be used to give privileges to user to do SELECT, INSERT, UPDATE and DELETE on a specific table or multiple tables. The REVOKE command is used to take a privilege away (default) or revoking specific command like UPDATE or DELETE based on requirements.
Query by Example (QBE) is a database query language for relational databases. It was devised by Moshé M. Zloof at IBM Research during the mid-1970s, in parallel to the development of SQL . [ 1 ] It is the first graphical query language, using visual tables where the user would enter commands, example elements and conditions.
A derived table is the use of referencing an SQL subquery in a FROM clause. Essentially, the derived table is a subquery that can be selected from or joined to. The derived table functionality allows the user to reference the subquery as a table. The derived table is sometimes referred to as an inline view or a subselect.
C# naming conventions generally follow the guidelines published by Microsoft for all .NET languages [21] (see the .NET section, below), but no conventions are enforced by the C# compiler. The Microsoft guidelines recommend the exclusive use of only PascalCase and camelCase , with the latter used only for method parameter names and method-local ...
The create command is used to establish a new database, table, index, or stored procedure. The CREATE statement in SQL creates a component in a relational database management system (RDBMS). In the SQL 1992 specification, the types of components that can be created are schemas, tables , views , domains, character sets , collations ...
For example, to undo a delete selection command, the object may contain a copy of the deleted text so that it can be re-inserted, if the delete selection command must be undone. Note that using a separate object for each invocation of a command is also an example of the chain of responsibility pattern. The term execute is also ambiguous.
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.