Gbase 8C - SQL reference 6 SQL syntax (10)

1. DROP OPERATOR CLASS

Function description

Remove an operator class .

Grammar format

DROP OPERATOR CLASS [ IF EXISTS ] name USING index_method [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the operator class does not exist , No error, just prompt ;
2. name： The name of an existing operator class , Can be modified by patterns ;

1. index_method： The name of the index method used by this operator class ;

1. CASCADE： Automatically delete objects that depend on this operator class （ For example index ）, And all objects that depend on those objects ;

1. RESTRICT： If any object depends on this operator class , Then refuse to delete , This is the default setting .

matters needing attention

Only the owner of the operator class can delete the operator class .

Example

remove B- Tree operator class widget_ops：

DROP OPERATOR CLASS widget_ops USING btree;

Grammar compatible

SQL There is no in the standard DROP OPERATOR CLASS sentence .

Related to the grammar

ALTER OPERATOR CLASS, CREATE OPERATOR CLASS, ALTER OPERATOR FAMILY, CREAT OPERATOR FAMILY, DROP OPERATOR FAMILY

1. DROP OPERATOR FAMILY

Function description

Remove an operator family .

Grammar format

DROP OPERATOR FAMILY [ IF EXISTS ] name USING index_method [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the operator family does not exist , No error, just prompt ;
2. name： The name of the existing operator family , Can be modified by patterns ;

1. index_method： The name of the index to which the operator family belongs ;

1. CASCADE： Automatically delete objects that depend on this operator family , And all objects that depend on those objects ;

1. RESTRICT： If any object depends on this operator family , Then refuse to delete , This is the default setting .

matters needing attention

Only the owner of the operator family can delete the operator family .

Example

remove B- Tree operator family float_ops：

DROP OPERATOR FAMILY float_ops USING btree;

Grammar compatible

SQL There is no in the standard DROP OPERATOR FAMILY sentence .

Related to the grammar

ALTER OPERATOR FAMILY, CREATE OPERATOR FAMILY, ALTER OPERATOR CLASS, CREATE OPERATOR CLASS, DROP OPERATOR CLASS

1. DROP OWNED

Function description

Delete the database object owned by a database role .

Grammar format

DROP OWNED BY { name | CURRENT_USER | SESSION_USER } [, ...] [ CASCADE | RESTRICT ]

Parameter description

1. name： The name of the role to be deleted ;

1. CASCADE： Automatically delete objects that depend on this role , And all objects that depend on those objects ;

1. RESTRICT： If any object depends on the role , Then refuse to delete , This is the default setting .

matters needing attention

After removing roles , All the roles share objects in the current database （ database , Table space ） Permissions on all objects on will be revoked .

But the database 、 Tablespaces will not be removed .

Grammar compatible

DROP OWNED The order is a PostgreSQL Expand .

Related to the grammar

REASSIGN OWNED, DROP ROLE

1. DROP POLICY

Function description

Remove a row level security policy .

Grammar format

DROP POLICY [ IF EXISTS ] name ON table_name [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the policy does not exist , No error, just prompt ;
2. name： Name of the policy to be deleted ;
3. table_name： The name of the table where the policy is located , Can be modified by patterns ;
4. CASCADE | RESTRICT： No object depends on this row's access control policy , This statement is meaningless .

matters needing attention

Only the owner of the table can remove the row level security policy .

Example

DROP POLICY test_rls ON test_r;

DROP POLICY

Grammar compatible

DROP POLICY It's a kind of PostgreSQL Expand .

Related to the grammar

CREATE POLICY, ALTER POLICY

1. DROP ROLE

Function description

Delete the specified role .

Grammar format

DROP ROLE [ IF EXISTS ] name [, ...]

Parameter description

1. IF EXISTS： If the role does not exist , No error, just prompt ;
2. name： The name of the role to be removed .

matters needing attention

Only system administrators can remove the administrator role . To remove the non administrator role , Need to have CREATEROLE jurisdiction .

The role in the database occupation cannot be removed . Before deleting roles , You need to delete all objects owned by the role and their permissions .

Example

DROP ROLE gbasedbt;

DROP ROLE

Grammar compatible

SQL The standard defines DROP ROLE, But it only allows you to delete one role at a time and connect with PostgreSQL The authority of is different .

Related to the grammar

CREATE ROLE, ALTER ROLE, SET ROLE

1. DROP RULE

Function description

Remove a rewrite rule .

Grammar format

DROP RULE [ IF EXISTS ] name ON table_name [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the rule does not exist , No error, just prompt ;
2. name： Name of the rule to be removed ;

1. table_name： The name of the table or view to which the rule applies , Can be modified by patterns ;

1. CASCADE： Automatically delete objects that depend on this rule , And all objects that depend on those objects ;

1. RESTRICT： If any object depends on this rule , Then refuse to delete , This is the default setting .

Example

DROP RULE newrule ON mytable;

DROP RULE

Grammar compatible

DROP RULE It's a PostgreSQL Language extension .

Related to the grammar

CREATE RULE, ALTER RULE

1. DROP SCHEMA

Function description

Remove a pattern .

Grammar format

DROP SCHEMA [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the mode does not exist , No error, just prompt ;
2. name： Name of the pattern ;

1. CASCADE： Automatically delete objects that depend on this pattern （ surface 、 Functions, etc ）, And all objects that depend on those objects ;

1. RESTRICT： If any object depends on this schema , Then refuse to delete , This is the default setting .

matters needing attention

Only the owner of the schema has permission to execute DROP SCHEMA command .

Example

DROP SCHEMA gbaseschema CASCADE;

DROP SCHEMA

Grammar compatible

DROP SCHEMA accord with SQL standard ,IF EXISTS It's a PostgreSQL Expand .

Related to the grammar

ALTER SCHEMA, CREATE SCHEMA

1. DROP SEQUENCE

Function description

Remove a sequence .

Grammar format

DROP SEQUENCE [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the sequence does not exist , No error, just prompt ;
2. name： The name of the sequence , Can be modified by patterns ;

1. CASCADE： Automatically delete objects that depend on this sequence , And all objects that depend on those objects ;

1. RESTRICT： If any object depends on the sequence , Then refuse to delete , This is the default setting .

matters needing attention

Only the owner of the sequence can delete the sequence .

Example

DROP SEQUENCE serial;

DROP SEQUENCE

Grammar compatible

DROP SEQUENCE accord with SQL standard , Only IF EXISTS The option is a PostgreSQL Expand .

Related to the grammar

CREATE SEQUENCE, ALTER SEQUENCE

1. DROP STATISTICS

Function description

Delete extended statistics .

Grammar format

DROP STATISTICS [ IF EXISTS ] name [, ...]

Parameter description

1. IF EXISTS： If the extended statistics does not exist , No error, just prompt ;
2. name： Name of statistical object to be deleted , Can be modified by patterns ;

matters needing attention

Only the owner of the statistical object 、 The owner of the schema or the system administrator can delete the statistical object .

Example

DROP STATISTICS IF EXISTS

    accounting.users_uid_creation,

    public.grants_user_role;

Grammar compatible

SQL There is no in the standard DROP STATISTICS command .

Related to the grammar

ALTER STATISTICS, CREATE STATISTICS

1. DROP TABLE

Function description

Remove table .

Grammar format

DROP TABLE [ IF EXISTS ] name [, ...] [ CASCADE | RESTRICT ]

Parameter description

1. IF EXISTS： If the table does not exist , No error, just prompt ;
2. name： Name of the table to be deleted , Can be modified by patterns ;

1. CASCADE： Automatically delete objects that depend on this table （ For example, view ）, And all objects that depend on those objects ;

1. RESTRICT： If any object depends on this table , Then refuse to delete , This is the default setting .

matters needing attention

DROP TABLE Will force the deletion of the specified table , After deleting the table , Indexes that depend on this table will be deleted , The functions and stored procedures that use this table cannot be executed . Delete partition table , All partitions in the partition table will be deleted at the same time .

Example

DROP TABLE t1;

DROP TABLE

Grammar compatible

This command conforms to SQL standard , However, the standard allows only one table to be deleted per command and IF EXISTS The option is a PostgreSQL Expand .

Related to the grammar

ALTER TABLE, CREATE TABLE