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The Log Trigger works writing the changes (INSERT, UPDATE and DELETE operations) on the table in another, history table, defined as following: CREATE TABLE HistoryTable ( Column1 Type1 , Column2 Type2 , : : Columnn Typen , StartDate DATETIME , EndDate DATETIME )
In Transact-SQL, both the DELETE and UPDATE statements are enhanced to enable data from another table to be used in the operation, without needing a subquery: DELETE accepts joined tables in the FROM clause, similarly to SELECT. When this is done, the name or alias of which table in the join is to be deleted from is placed between DELETE and FROM.
An SQL UPDATE statement changes the data of one or more records in a table. Either all the rows can be updated, or a subset may be chosen using a condition. The UPDATE statement has the following form: [1] UPDATE table_name SET column_name = value [, column_name = value ...] [WHERE condition]
In relational databases a virtual column is a table column whose value(s) is automatically computed using other columns values, or another deterministic expression. Virtual columns are defined of SQL:2003 as Generated Column, [1] and are only implemented by some DBMSs, like MariaDB, SQL Server, Oracle, PostgreSQL, SQLite and Firebird (database server) (COMPUTED BY syntax).
A right join is employed over the Target (the INTO table) and the Source (the USING table / view / sub-query)--where Target is the left table and Source is the right one. The four possible combinations yield these rules: If the ON field(s) in the Source matches the ON field(s) in the Target, then UPDATE
A common table expression, or CTE, (in SQL) is a temporary named result set, derived from a simple query and defined within the execution scope of a SELECT, INSERT, UPDATE, or DELETE statement. CTEs can be thought of as alternatives to derived tables ( subquery ), views , and inline user-defined functions.
Cursors can not only be used to fetch data from the DBMS into an application but also to identify a row in a table to be updated or deleted. The SQL:2003 standard defines positioned update and positioned delete SQL statements for that purpose. Such statements do not use a regular WHERE clause with predicates. Instead, a cursor identifies the row.
A schema crosswalk is a table that shows equivalent elements (or "fields") in more than one database schema.It maps the elements in one schema to the equivalent elements in another.