Before we explain why you’d need aDDL script, it is essential for you to understand what it is. DDL stands forData Definition Language. This is a set of SQL commands used for creating, modifying, and removing database objects; its primary commands areCREATE,ALTER,DROP, andTRUNCATE. These...
DQL is also a subset of SQL. One of the most common commands in DQL isSELECT. It lets users get data from a database table and perform some operation on it. When the statement is executed, the result is compiled into a
What is a TTL table? This topic describes the definition and principle of Time to Live (TTL) tables. Overview PolarDB-X allows you to specify the local_partition_definition syntax in a DDL statement to create a TTL table. A TTL table partitions each physical table by time and manages the ...
Figure 2: SQL statement created from the input in Figure 1 When the relational database receives this SQL statement, it first searches for a row in the USERS table where the USER NAME is "Ken Sato". Since the user name "Ken Sato" already exists, the relational database moves on to...
The SELECT statement also does not produce rollback or redo log entries. The TRUNCATE statement, on the other hand, does change data but automatically executes a COMMIT statement. The TRUNCATE statement is therefore a DDL statement.doi:10.1016/B978-155558345-3/50006-9Gavin Powell...
Data Definition Language (DDL) statements are used to define the structure of the data in the database such as tables, procedures, functions, views, etc. The following table lists DDL statements: StatementDescription CREATE Create a new object(table, procedure, function, view etc.) in the data...
Database Proxy is a network proxy service between GaussDB(for MySQL) and the application service. It is used to proxy all the requests for the application service to acce
IF EXISTS (SELECT * FROM sys.objects WHERE object_id = OBJECT_ID(N'[People]') AND type in (N'U')) DROP TABLE [People] GO SET ANSI_NULLS ON GO SET...
SQL is a non-procedural language. Each SQL statement is an individual execution unit, independent of other statements. There is no conditional statements, jumping statements or looping statements to group multiple statements together into a complex execution unit. There is no way to define a ...
Commonly used DDL in SQL querying are CREATE, ALTER, DROP, and TRUNCATE. Create This command builds a new table and has a predefined syntax. The CREATE statement syntax is: CREATE TABLE [table name] ([column definitions]) [table parameters]; ...