Search results
Results from the WOW.Com Content Network
DELETE requires a shared table lock; Triggers fire; DELETE can be used in the case of: database link; DELETE returns the number of records deleted; Transaction log - DELETE needs to read records, check constraints, update block, update indexes, and generate redo / undo. All of this takes time, hence it takes time much longer than with TRUNCATE
Without an ORDER BY clause, the order of rows returned by an SQL query is undefined. The DISTINCT keyword [5] eliminates duplicate data. [6] The following example of a SELECT query returns a list of expensive books. The query retrieves all rows from the Book table in which the price column contains a value greater
In SQL, the TRUNCATE TABLE statement is a Data Definition Language (DDL) operation that deletes all rows of a table without causing a triggered action. [1] The result of this operation quickly removes all data from a table, typically bypassing a number of integrity enforcing mechanisms.
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).
Additionally there is a single-row version, UPDATE OR INSERT INTO tablename (columns) VALUES (values) [MATCHING (columns)], but the latter does not give you the option to take different actions on insert versus update (e.g. setting a new sequence value only for new rows, not for existing ones.)
When creating a trigger to determine if it is statement or row level simply include the FOR EACH ROW clause for a row level, or omit the clause for a statement level. Be cautious of using additional INSERT/UPDATE/DELETE commands within your trigger, because trigger recursion is possible, causing unwanted behavior. In the examples below each ...
If you’re stuck on today’s Wordle answer, we’re here to help—but beware of spoilers for Wordle 1271 ahead. Let's start with a few hints.
Transact-SQL (T-SQL) is Microsoft's and Sybase's proprietary extension to the SQL (Structured Query Language) used to interact with relational databases.T-SQL expands on the SQL standard to include procedural programming, local variables, various support functions for string processing, date processing, mathematics, etc. and changes to the DELETE and UPDATE statements.