DDL Syntax Overview
Data definition language (DDL) is used to define or modify an object in a database, such as a table, an index, or a view.

GaussDB does not support DDL if its CN is unavailable. For example, if a CN in cluster is faulty, creating a database or a table will fail.
Defining a Database
A database is the warehouse for organizing, storing, and managing data. Defining a database includes: creating a database, altering the database attributes, and dropping the database. For details about related SQL statements, see Table 1.
Defining a Schema
A schema is the set of a group of database objects and is used to control the access to the database objects. For details about related SQL statements, see Table 2.
Defining a Tablespace
A tablespace is used to manage data objects and corresponds to a catalog on a disk. For details about related SQL statements, see Table 3.
Defining a Table
A table is a special data structure in a database and is used to store data objects and relationship between data objects. For details about related SQL statements, see Table 4.
Defining a Partitioned Table
A partitioned table is a logical table used to improve query performance and does not store data (data is stored in ordinary tables). For details about related SQL statements, see Table 5.
Defining an Index
An index indicates the sequence of values in one or more columns in a database table. It is a data structure that improves the speed of data access to specific information in a database table. For details about related SQL statements, see Table 6.
Defining a Stored Procedure
A stored procedure is a set of SQL statements for achieving specific functions and is stored in the database after compiling. Users can specify a name and provide parameters (if necessary) to execute the stored procedure. For details about related SQL statements, see Table 7.
Defining a Function
In GaussDB, a function is similar to a stored procedure, which is a set of SQL statements. The function and stored procedure are used the same. For details about related SQL statements, see Table 8.
Defining a View
A view is a virtual table exported from one or more basic tables. It is used to control data accesses of users. Table 9 lists the related SQL statements.
Defining a Cursor
To process SQL statements, the stored procedure process allocates a memory fragment to store the context. Cursors are handles or pointers to the context area. With a cursor, the stored procedure can control alterations in context areas. For details, see Table 10.
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