DROP SEQUENCE
- reference
- Couchbase Server 7.6
The DROP SEQUENCE statement enables you to drop a sequence in a given scope.
Purpose
A sequence is a construct that returns a sequence of integer values, one at a time, rather like a counter. Each time you request the next value for a sequence, an increment is added to the previous value, and the resulting value is returned. This is useful for generating values such as sequential ID numbers, where you need the Query service to keep track of the current value from one query to the next.
Prerequisites
To execute the DROP SEQUENCE statement, you must have the Query Manage Sequences privilege granted on the scope. For more details about user roles, see Authorization.
Syntax
drop-sequence ::= 'DROP' 'SEQUENCE' ( sequence ( 'IF' 'EXISTS' )? |
( 'IF' 'EXISTS' )? sequence )
sequence |
(Required) A name that identifies the sequence within a namespace, bucket, and scope. See Sequence Name below. |
Sequence Name
sequence ::= ( ( namespace ':' )? bucket '.' scope '.' )? identifier
The sequence name specifies the name of the sequence to drop.
Each sequence is associated with a given namespace, bucket, and scope. You must specify the namespace, bucket, and scope to refer to the sequence correctly.
namespace |
(Optional) The namespace of the bucket which contains the sequence you want to drop. |
bucket |
(Optional) The bucket which contains the sequence you want to drop. |
scope |
(Optional) The scope which contains the sequence you want to drop. |
identifier |
(Required) The name of the sequence. The sequence name is case-sensitive. |
Currently, only the default
namespace is available.
If you omit the namespace, the default namespace in the current session is used.
If the query context is set, you can omit the bucket and scope from the statement. In this case, the bucket and scope for the sequence are taken from the query context.
The namespace, bucket, scope, and sequence name must follow the rules for identifiers. If the namespace, bucket, scope, or sequence name contain any special characters such as hyphens (-), you must wrap that part of the expression in backticks (` `).
IF EXISTS Clause
The optional IF EXISTS
clause enables the statement to complete successfully when the specified sequence doesn’t exist.
When the sequence does not exist within the specified context:
-
If this clause is not present, an error is generated.
-
If this clause is present, the statement does nothing and completes without error.
Examples
To try the examples in this section, set the query context to the inventory
scope in the travel sample dataset.
For more information, see Query Context.
This statement drops a sequence in the specified scope.
DROP SEQUENCE `travel-sample`.inventory.seq1;
This statement drops a sequence in the current query context, if a sequence of that name exists.
DROP SEQUENCE seq2 IF EXISTS;
Related Links
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To create a sequence, see CREATE SEQUENCE.
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To alter a sequence, see ALTER SEQUENCE.
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To use a sequence in an expression, see Sequence Operators.
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To monitor sequences, see Monitor Sequences.