ALTER DATABASE (Transact-SQL)

Modifies certain configuration options of a database.

This article provides the syntax, arguments, remarks, permissions, and examples for whichever SQL product you choose.

For more information about the syntax conventions, see Transact-SQL Syntax Conventions.

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SQL Server

Overview

In SQL Server, this statement modifies a database, or the files and filegroups associated with the database. Adds or removes files and filegroups from a database, changes the attributes of a database or its files and filegroups, changes the database collation, and sets database options. Database snapshots cannot be modified. To modify database options associated with replication, use sp_replicationdboption.

Because of its length, the ALTER DATABASE syntax is separated into the multiple articles.

ALTER DATABASE
The current article provides the syntax and related information for changing the name and the collation of a database.

ALTER DATABASE File and Filegroup Options
Provides the syntax and related information for adding and removing files and filegroups from a database, and for changing the attributes of the files and filegroups.

ALTER DATABASE SET Options
Provides the syntax and related information for changing the attributes of a database by using the SET options of ALTER DATABASE.

ALTER DATABASE Database Mirroring
Provides the syntax and related information for the SET options of ALTER DATABASE that are related to database mirroring.

ALTER DATABASE SET HADR
Provides the syntax and related information for the Always On availability groups options of ALTER DATABASE for configuring a secondary database on a secondary replica of an Always On availability group.

ALTER DATABASE Compatibility Level
Provides the syntax and related information for the SET options of ALTER DATABASE that are related to database compatibility levels.

Syntax

-- SQL Server Syntax  
ALTER DATABASE { database_name  | CURRENT }  
{  
    MODIFY NAME = new_database_name   
  | COLLATE collation_name  
  | <file_and_filegroup_options>  
  | SET <option_spec> [ ,...n ] [ WITH <termination> ] 
  | SET COMPATIBILITY_LEVEL = { 140 | 130 | 120 | 110 | 100 | 90 }   

}  
[;]  

<file_and_filegroup_options>::=  
  <add_or_modify_files>::=  
  <filespec>::=   
  <add_or_modify_filegroups>::=  
  <filegroup_updatability_option>::=  

<option_spec>::=  
  <auto_option> ::=   
  <change_tracking_option> ::=  
  <cursor_option> ::=   
  <database_mirroring_option> ::=   
  <date_correlation_optimization_option> ::=  
  <db_encryption_option> ::=  
  <db_state_option> ::=  
  <db_update_option> ::=  
  <db_user_access_option> ::=  <delayed_durability_option> ::=  <external_access_option> ::=  
  <FILESTREAM_options> ::=  
  <HADR_options> ::=    
  <parameterization_option> ::=  
  <query_store_options> ::=  
  <recovery_option> ::=   
  <service_broker_option> ::=  
  <snapshot_option> ::=  
  <sql_option> ::=   
  <termination> ::=  

<compatibility_level>
   { 140 | 130 | 120 | 110 | 100 | 90 }   

Arguments

database_name
Is the name of the database to be modified.

Note

This option is not available in a Contained Database.

CURRENT
Applies to: SQL Server 2012 (11.x) through SQL Server 2017.

Designates that the current database in use should be altered.

MODIFY NAME =new_database_name
Renames the database with the name specified as new_database_name.

COLLATE collation_name
Specifies the collation for the database. collation_name can be either a Windows collation name or a SQL collation name. If not specified, the database is assigned the collation of the instance of SQL Server.

When creating databases with other than the default collation, the data in the database always respects the specified collation. For SQL Server, when creating a contained database, the internal catalog information is maintained using the SQL Server default collation, Latin1_General_100_CI_AS_WS_KS_SC.

For more information about the Windows and SQL collation names, see COLLATE.

<delayed_durability_option> ::=
Applies to: SQL Server 2014 (12.x) through SQL Server 2017.

For more information see ALTER DATABASE SET Options and Control Transaction Durability.

<file_and_filegroup_options>::=
For more information, see ALTER DATABASE File and Filegroup Options.

Remarks

To remove a database, use DROP DATABASE.

To decrease the size of a database, use DBCC SHRINKDATABASE.

The ALTER DATABASE statement must run in autocommit mode (the default transaction management mode) and is not allowed in an explicit or implicit transaction.

The state of a database file (for example, online or offline), is maintained independently from the state of the database. For more information, see File States. The state of the files within a filegroup determines the availability of the whole filegroup. For a filegroup to be available, all files within the filegroup must be online. If a filegroup is offline, any try to access the filegroup by an SQL statement will fail with an error. When you build query plans for SELECT statements, the query optimizer avoids nonclustered indexes and indexed views that reside in offline filegroups. This enables these statements to succeed. However, if the offline filegroup contains the heap or clustered index of the target table, the SELECT statements fail. Additionally, any INSERT, UPDATE, or DELETE statement that modifies a table with any index in an offline filegroup will fail.

When a database is in the RESTORING state, most ALTER DATABASE statements will fail. The exception is setting database mirroring options. A database may be in the RESTORING state during an active restore operation or when a restore operation of a database or log file fails because of a corrupted backup file.

The plan cache for the instance of SQL Server is cleared by setting one of the following options.

OFFLINE READ_WRITE
ONLINE MODIFY FILEGROUP DEFAULT
MODIFY_NAME MODIFY FILEGROUP READ_WRITE
COLLATE MODIFY FILEGROUP READ_ONLY
READ_ONLY PAGE_VERIFY

Clearing the plan cache causes a recompilation of all subsequent execution plans and can cause a sudden, temporary decrease in query performance. For each cleared cachestore in the plan cache, the SQL Server error log contains the following informational message: " SQL Server has encountered %d occurrence(s) of cachestore flush for the '%s' cachestore (part of plan cache) due to some database maintenance or reconfigure operations". This message is logged every five minutes as long as the cache is flushed within that time interval.

The procedure cache is also flushed in the following scenarios:

  • A database has the AUTO_CLOSE database option set to ON. When no user connection references or uses the database, the background task tries to close and shut down the database automatically.
  • You run several queries against a database that has default options. Then, the database is dropped.
  • A database snapshot for a source database is dropped.
  • You successfully rebuild the transaction log for a database.
  • You restore a database backup.
  • You detach a database.

Changing the Database Collation

Before you apply a different collation to a database, make sure that the following conditions are in place:

  • You are the only one currently using the database.
  • No schema-bound object depends on the collation of the database.

    If the following objects, which depend on the database collation, exist in the database, the ALTER DATABASEdatabase_nameCOLLATE statement will fail. SQL Server will return an error message for each object blocking the ALTER action:

    • User-defined functions and views created with SCHEMABINDING.

    • Computed columns.

    • CHECK constraints.

    • Table-valued functions that return tables with character columns with collations inherited from the default database collation.

      Dependency information for non-schema-bound entities is automatically updated when the database collation is changed.

Changing the database collation does not create duplicates among any system names for the database objects. If duplicate names result from the changed collation, the following namespaces may cause the failure of a database collation change:

  • Object names such as a procedure, table, trigger, or view.
  • Schema names.
  • Principals such as a group, role, or user.
  • Scalar-type names such as system and user-defined types.
  • Full-text catalog names.
  • Column or parameter names within an object.
  • Index names within a table.

Duplicate names resulting from the new collation will cause the change action to fail, and SQL Server will return an error message specifying the namespace where the duplicate was found.

Viewing Database Information

You can use catalog views, system functions, and system stored procedures to return information about databases, files, and filegroups.

Permissions

Requires ALTER permission on the database.

Examples

A. Changing the name of a database

The following example changes the name of the AdventureWorks2012 database to Northwind.

USE master;  
GO  
ALTER DATABASE AdventureWorks2012  
Modify Name = Northwind ;  
GO  

B. Changing the collation of a database

The following example creates a database named testdb with the SQL_Latin1_General_CP1_CI_AS collation, and then changes the collation of the testdb database to COLLATE French_CI_AI.

Applies to: SQL Server 2008 through SQL Server 2017.

USE master;  
GO  

CREATE DATABASE testdb  
COLLATE SQL_Latin1_General_CP1_CI_AS ;  
GO  

ALTER DATABASE testDB  
COLLATE French_CI_AI ;  
GO  

See Also

 

Azure SQL Database logical server

Overview

In Azure SQL Database, use this statement to modify a database on a logical server. Use this statement to change the name of a database, change the edition and service objective of the database, join or remove the database to or from an elastic pool, set database options, add or remove the database as a secondary in a geo-replication relationship, and set the database compatibility level.

Because of its length, the ALTER DATABASE syntax is separated into the multiple articles.

ALTER DATABASE
The current article provides the syntax and related information for changing the name and the collation of a database.

ALTER DATABASE SET Options
Provides the syntax and related information for changing the attributes of a database by using the SET options of ALTER DATABASE.

ALTER DATABASE Compatibility Level
Provides the syntax and related information for the SET options of ALTER DATABASE that are related to database compatibility levels.

Syntax

-- Azure SQL Database Syntax  
ALTER DATABASE { database_name | CURRENT }  
{  
    MODIFY NAME = new_database_name  
  | MODIFY ( <edition_options> [, ... n] ) 
  | SET { <option_spec> [ ,... n ] WITH <termination>} 
  | SET COMPATIBILITY_LEVEL = { 140 | 130 | 120 | 110 | 100 }   
  | ADD SECONDARY ON SERVER <partner_server_name>  
    [WITH ( <add-secondary-option>::= [, ... n] ) ]  
  | REMOVE SECONDARY ON SERVER <partner_server_name>  
  | FAILOVER  
  | FORCE_FAILOVER_ALLOW_DATA_LOSS  
}  
[;] 

<edition_options> ::= 
{  

  MAXSIZE = { 100 MB | 250 MB | 500 MB | 1 … 1024 … 4096 GB }  
  | EDITION = { 'basic' | 'standard' | 'premium' | 'GeneralPurpose' | 'BusinessCritical'} 
  | SERVICE_OBJECTIVE = 
       {  <service-objective>
       | { ELASTIC_POOL (name = <elastic_pool_name>) } 
       } 
}  

<add-secondary-option> ::=  
   {  
      ALLOW_CONNECTIONS = { ALL | NO }  
     | SERVICE_OBJECTIVE = 
       {  <service-objective> 
       | { ELASTIC_POOL ( name = <elastic_pool_name>) } 
       } 
   }  

<service-objective> ::=  { 'S0' | 'S1' | 'S2' | 'S3'| 'S4'| 'S6'| 'S7'| 'S9'| 'S12' |
       | 'P1' | 'P2' | 'P4'| 'P6' | 'P11'  | 'P15'
      | 'GP_GEN4_1' | 'GP_GEN4_2' | 'GP_GEN4_4' | 'GP_GEN4_8' | 'GP_GEN4_16' | 'GP_GEN4_24' |
      | 'BC_GEN4_1' | 'BC_GEN4_2' | 'BC_GEN4_4' | 'BC_GEN4_8' | 'BC_GEN4_16' | 'BC_GEN4_24' |
      | 'GP_GEN5_2' | 'GP_GEN5_4' | 'GP_GEN5_8' | 'GP_GEN5_16' | 'GP_GEN5_24' | 'GP_GEN5_32' | 'GP_GEN5_48' | 'GP_GEN5_80' |
      | 'BC_GEN5_2' | 'BC_GEN5_4' | 'BC_GEN5_8' | 'BC_GEN5_16' | 'BC_GEN5_24' | 'BC_GEN5_32' | 'BC_GEN5_48' | 'BC_GEN5_80' |
      }

<option_spec> ::= 
{  
    <auto_option> 
  | <change_tracking_option> 
  | <cursor_option> 
  | <db_encryption_option>  
  | <db_update_option> 
  | <db_user_access_option> 
  | <delayed_durability_option>  
  | <parameterization_option>  
  | <query_store_options>  
  | <snapshot_option>  
  | <sql_option> 
  | <target_recovery_time_option> 
  | <termination>  
  | <temporal_history_retention>  
}  

Arguments

database_name

Is the name of the database to be modified.

CURRENT

Designates that the current database in use should be altered.

MODIFY NAME =new_database_name

Renames the database with the name specified as new_database_name. The following example changes the name of a database db1 to db2:

ALTER DATABASE db1  
    MODIFY Name = db2 ;  

MODIFY (EDITION = ['basic' | 'standard' | 'premium' |'GeneralPurpose' | 'BusinessCritical'])

Changes the service tier of the database.

The following example changes edition to premium:

ALTER DATABASE current 
    MODIFY (EDITION = 'premium');

EDITION change fails if the MAXSIZE property for the database is set to a value outside the valid range supported by that edition.

MODIFY (MAXSIZE = [100 MB | 500 MB | 1 | 1024…4096] GB)

Specifies the maximum size of the database. The maximum size must comply with the valid set of values for the EDITION property of the database. Changing the maximum size of the database may cause the database EDITION to be changed. Following table lists the supported MAXSIZE values and the defaults (D) for the SQL Database service tiers.

DTU-based model

MAXSIZE Basic S0-S2 S3-S12 P1-P6 P11-P15
100 MB
250 MB
500 MB
1 GB
2 GB √ (D)
5 GB N/A
10 GB N/A
20 GB N/A
30 GB N/A
40 GB N/A
50 GB N/A
100 GB N/A
150 GB N/A
200 GB N/A
250 GB N/A √ (D) √ (D)
300 GB N/A
400 GB N/A
500 GB N/A √ (D)
750 GB N/A
1024 GB N/A √ (D)
From 1024 GB up to 4096 GB in increments of 256 GB* N/A N/A N/A N/A

* P11 and P15 allow MAXSIZE up to 4 TB with 1024 GB being the default size. P11 and P15 can use up to 4 TB of included storage at no additional charge. In the Premium tier, MAXSIZE greater than 1 TB is currently available in the following regions: US East2, West US, US Gov Virginia, West Europe, Germany Central, South East Asia, Japan East, Australia East, Canada Central, and Canada East. For additional details regarding resource limitations for the DTU-based model, see DTU-based resource limits.

The MAXSIZE value for the DTU-based model, if specified, has to be a valid value shown in the table above for the service tier specified.

vCore-based model

General Purpose service tier - Generation 4 compute platform

MAXSIZE GP_Gen4_1 GP_Gen4_2 GP_Gen4_4 GP_Gen4_8 GP_Gen4_16 GP4_24
Max data size (GB) 1024 1024 1536 3072 4096 4096

General Purpose service tier - Generation 5 compute platform

MAXSIZE GP_Gen5_2 GP_Gen5_4 GP_Gen5_8 GP_Gen5_16 GP_Gen5_24 GP_Gen5_32 GP_Gen5_48 GP_Gen5_80
Max data size (GB) 1024 1024 1536 3072 4096 4096 4096 4096

Business Critical service tier - Generation 4 compute platform

Performance level BC_Gen4_1 BC_Gen4_2 BC_Gen4_4 BC_Gen4_8 BC_Gen4_16
Max data size (GB) 1024 1024 1024 1024 1024

Business Critical service tier - Generation 5 compute platform

MAXSIZE BC_Gen5_2 BC_Gen5_4 BC_Gen5_8 BC_Gen5_16 BC_Gen5_24 BC_Gen5_32 BC_Gen5_48 BC_Gen5_80
Max data size (GB) 1024 1024 1024 1024 2048 4096 4096 4096

If no MAXSIZEvalue is set when using the vCore model, the default is 32 GB. For additional details regarding resource limitations for vCore-based model, see vCore-based resource limits.

The following rules apply to MAXSIZE and EDITION arguments:

  • If EDITION is specified but MAXSIZE is not specified, the default value for the edition is used. For example, is the EDITION is set to Standard, and the MAXSIZE is not specified, then the MAXSIZE is automatically set to 500 MB.

  • If neither MAXSIZE nor EDITION is specified, the EDITION is set to Standard (S0), and MAXSIZE is set to 250 GB.

MODIFY (SERVICE_OBJECTIVE = <service-objective>)

Specifies the performance level. The following example changes service objective of a premium database to P6:

ALTER DATABASE current 
    MODIFY (SERVICE_OBJECTIVE = 'P6');

Specifies the performance level. Available values for service objective are: S0, S1, S2, S3, S4, S6, S7, S9, S12, P1, P2, P4, P6, P11, P15, GP_GEN4_1, GP_GEN4_2, GP_GEN4_4, GP_GEN4_8, GP_GEN4_16, GP_GEN4_24, BC_GEN4_1 BC_GEN4_2 BC_GEN4_4 BC_GEN4_8 BC_GEN4_16, BC_GEN4_24, GP_Gen5_2, GP_Gen5_4, GP_Gen5_8, GP_Gen5_16, GP_Gen5_24, GP_Gen5_32, GP_Gen5_48, GP_Gen5_80, BC_Gen5_2, BC_Gen5_4, BC_Gen5_8, BC_Gen5_16, BC_Gen5_24, BC_Gen5_32, BC_Gen5_48, BC_Gen5_80.

For service objective descriptions and more information about the size, editions, and the service objectives combinations, see Azure SQL Database Service Tiers and Performance Levels, DTU-based resource limits and vCore-based resource limits. Support for PRS service objectives have been removed. For questions, use this e-mail alias: premium-rs@microsoft.com.

MODIFY (SERVICE_OBJECTIVE = ELASTIC_POOL (name = <elastic_pool_name>)

To add an existing database to an elastic pool, set the SERVICE_OBJECTIVE of the database to ELASTIC_POOL and provide the name of the elastic pool. You can also use this option to change the database to a different elastic pool within the same server. For more information, see Create and manage a SQL Database elastic pool. To remove a database from an elastic pool, use ALTER DATABASE to set the SERVICE_OBJECTIVE to a single database performance level.

ADD SECONDARY ON SERVER <partner_server_name>

Creates a geo-replication secondary database with the same name on a partner server, making the local database into a geo-replication primary, and begins asynchronously replicating data from the primary to the new secondary. If a database with the same name already exists on the secondary, the command fails. The command is executed on the master database on the server hosting the local database that becomes the primary.

WITH ALLOW_CONNECTIONS { ALL | NO }

When ALLOW_CONNECTIONS is not specified, it is set to ALL by default. If it is set ALL, it is a read-only database that allows all logins with the appropriate permissions to connect.

WITH SERVICE_OBJECTIVE { S0, S1, S2, S3, S4, S6, S7, S9, S12, P1, P2, P4, P6, P11, P15, GP_GEN4_1, GP_GEN4_2, GP_GEN4_4, GP_GEN4_8, GP_GEN4_16, GP_GEN4_24, BC_GEN4_1 BC_GEN4_2 BC_GEN4_4 BC_GEN4_8 BC_GEN4_16, BC_GEN4_24, GP_Gen5_2, GP_Gen5_4, GP_Gen5_8, GP_Gen5_16, GP_Gen5_24, GP_Gen5_32, GP_Gen5_48, GP_Gen5_80, BC_Gen5_2, BC_Gen5_4, BC_Gen5_8, BC_Gen5_16, BC_Gen5_24, BC_Gen5_32, BC_Gen5_48, BC_Gen5_80 }

When SERVICE_OBJECTIVE is not specified, the secondary database is created at the same service level as the primary database. When SERVICE_OBJECTIVE is specified, the secondary database is created at the specified level. This option supports creating geo-replicated secondaries with less expensive service levels. The SERVICE_OBJECTIVE specified must be within the same edition as the source. For example, you cannot specify S0 if the edition is premium.

ELASTIC_POOL (name = <elastic_pool_name>)

When ELASTIC_POOL is not specified, the secondary database is not created in an elastic pool. When ELASTIC_POOL is specified, the secondary database is created in the specified pool.

Important

The user executing the ADD SECONDARY command must be DBManager on primary server, have db_owner membership in local database, and DBManager on secondary server.

REMOVE SECONDARY ON SERVER <partner_server_name>

Removes the specified geo-replicated secondary database on the specified server. The command is executed on the master database on the server hosting the primary database.

Important

The user executing the REMOVE SECONDARY command must be DBManager on the primary server.

FAILOVER

Promotes the secondary database in geo-replication partnership on which the command is executed to become the primary and demotes the current primary to become the new secondary. As part of this process, the geo-replication mode is temporarily switched from asynchronous mode to synchronous mode. During the failover process:

  1. The primary stops taking new transactions.

  2. All outstanding transactions are flushed to the secondary.

  3. The secondary becomes the primary and begins asynchronous geo-replication with the old primary / the new secondary.

This sequence ensures that no data loss occurs. The period during which both databases are unavailable is on the order of 0-25 seconds while the roles are switched. The total operation should take no longer than about one minute. If the primary database is unavailable when this command is issued, the command fails with an error message indicating that the primary database is not available. If the failover process does not complete and appears stuck, you can use the force failover command and accept data loss - and then, if you need to recover the lost data, call devops (CSS) to recover the lost data.

Important

The user executing the FAILOVER command must be DBManager on both the primary server and the secondary server.

FORCE_FAILOVER_ALLOW_DATA_LOSS

Promotes the secondary database in geo-replication partnership on which the command is executed to become the primary and demotes the current primary to become the new secondary. Use this command only when the current primary is no longer available. It is designed for disaster recovery only, when restoring availability is critical, and some data loss is acceptable.

During a forced failover:

  1. The specified secondary database immediately becomes the primary database and begins accepting new transactions.

  2. When the original primary can reconnect with the new primary, an incremental backup is taken on the original primary, and the original primary becomes a new secondary.

  3. To recover data from this incremental backup on the old primary, the user engages devops/CSS.

  4. If there are additional secondaries, they are automatically reconfigured to become secondaries of the new primary. This process is asynchronous and there may be a delay until this process completes. Until the reconfiguration has completed, the secondaries continue to be secondaries of the old primary.

Important

The user executing the FORCE_FAILOVER_ALLOW_DATA_LOSS command must be DBManager on both the primary server and the secondary server.

Remarks

To remove a database, use DROP DATABASE.
To decrease the size of a database, use DBCC SHRINKDATABASE.

The ALTER DATABASE statement must run in autocommit mode (the default transaction management mode) and is not allowed in an explicit or implicit transaction.

Clearing the plan cache causes a recompilation of all subsequent execution plans and can cause a sudden, temporary decrease in query performance. For each cleared cachestore in the plan cache, the SQL Server error log contains the following informational message: " SQL Server has encountered %d occurrence(s) of cachestore flush for the '%s' cachestore (part of plan cache) due to some database maintenance or reconfigure operations". This message is logged every five minutes as long as the cache is flushed within that time interval.

The procedure cache is also flushed in the following scenario: You run several queries against a database that has default options. Then, the database is dropped.

Viewing Database Information

You can use catalog views, system functions, and system stored procedures to return information about databases, files, and filegroups.

Permissions

Only the server-level principal login (created by the provisioning process) or members of the dbmanager database role can alter a database.

Important

The owner of the database cannot alter the database unless they are a member of the dbmanager role.

Examples

A. Check the edition options and change them:

SELECT Edition = DATABASEPROPERTYEX('db1', 'EDITION'),
        ServiceObjective = DATABASEPROPERTYEX('db1', 'ServiceObjective'),
        MaxSizeInBytes =  DATABASEPROPERTYEX('db1', 'MaxSizeInBytes');

ALTER DATABASE [db1] MODIFY (EDITION = 'Premium', MAXSIZE = 1024 GB, SERVICE_OBJECTIVE = 'P15');

B. Moving a database to a different elastic pool

Moves an existing database into a pool named pool1:

ALTER DATABASE db1   
MODIFY ( SERVICE_OBJECTIVE = ELASTIC_POOL ( name = pool1 ) ) ;  

C. Add a Geo-Replication Secondary

Creates a readable secondary database db1 on server secondaryserver of the db1 on the local server.

ALTER DATABASE db1   
ADD SECONDARY ON SERVER secondaryserver   
WITH ( ALLOW_CONNECTIONS = ALL )  

D. Remove a Geo-Replication Secondary

Removes the secondary database db1 on server secondaryserver.

ALTER DATABASE db1   
REMOVE SECONDARY ON SERVER testsecondaryserver   

E. Failover to a Geo-Replication Secondary

Promotes a secondary database db1 on server secondaryserver to become the new primary database when executed on server secondaryserver.

ALTER DATABASE db1 FAILOVER  

See also

CREATE DATABASE - Azure SQL Database
DATABASEPROPERTYEX
DROP DATABASE
SET TRANSACTION ISOLATION LEVEL
EVENTDATA
sp_configure
sp_spaceused
sys.databases
sys.database_files
sys.database_mirroring_witnesses
sys.data_spaces
sys.filegroups
sys.master_files
System Databases

         
SQL Server SQL Database
logical server
* SQL Database
Managed Instance *
SQL Data
Warehouse
SQL Parallel
Data Warehouse

 

Azure SQL Database Managed Instance

Overview

In Azure SQL Database Managed Instance, use this statement to set database options.

Because of its length, the ALTER DATABASE syntax is separated into the multiple articles.

ALTER DATABASE
The current article provides the syntax and related information for setting file and filegroup options, for setting database options, and for setting the database compatibility level.

ALTER DATABASE File and Filegroup Options Provides the syntax and related information for adding and removing files and filegroups from a database, and for changing the attributes of the files and filegroups.

ALTER DATABASE SET Options Provides the syntax and related information for changing the attributes of a database by using the SET options of ALTER DATABASE.

ALTER DATABASE Compatibility Level Provides the syntax and related information for the SET options of ALTER DATABASE that are related to database compatibility levels.

Syntax

-- Azure SQL Database Syntax  
ALTER DATABASE { database_name | CURRENT }  
{  
    <file_and_filegroup_options>  
  | SET <option_spec> [ ,...n ]  
  | SET COMPATIBILITY_LEVEL = { 140 | 130 | 120 | 110 | 100 }   
}  
[;] 

<file_and_filegroup_options>::=  
  <add_or_modify_files>::=  
  <filespec>::=   
  <add_or_modify_filegroups>::=  
  <filegroup_updatability_option>::=  

<option_spec> ::= 
{  
    <auto_option> 
  | <change_tracking_option> 
  | <cursor_option> 
  | <db_encryption_option>  
  | <db_update_option> 
  | <db_user_access_option> 
  | <delayed_durability_option>  
  | <parameterization_option>  
  | <query_store_options>  
  | <snapshot_option>  
  | <sql_option> 
  | <target_recovery_time_option> 
  | <temporal_history_retention>  
}  

Arguments

database_name

Is the name of the database to be modified.

CURRENT

Designates that the current database in use should be altered.

Remarks

To remove a database, use DROP DATABASE.
To decrease the size of a database, use DBCC SHRINKDATABASE.

The ALTER DATABASE statement must run in autocommit mode (the default transaction management mode) and is not allowed in an explicit or implicit transaction.

Clearing the plan cache causes a recompilation of all subsequent execution plans and can cause a sudden, temporary decrease in query performance. For each cleared cachestore in the plan cache, the SQL Server error log contains the following informational message: " SQL Server has encountered %d occurrence(s) of cachestore flush for the '%s' cachestore (part of plan cache) due to some database maintenance or reconfigure operations". This message is logged every five minutes as long as the cache is flushed within that time interval.

The procedure cache is also flushed in the following scenario: You run several queries against a database that has default options. Then, the database is dropped.

Viewing Database Information

You can use catalog views, system functions, and system stored procedures to return information about databases, files, and filegroups.

Permissions

Only the server-level principal login (created by the provisioning process) or members of the dbmanager database role can alter a database.

Important

The owner of the database cannot alter the database unless they are a member of the dbmanager role.

Examples

The following examples show you how to set automatic tuning and how to add a file in a managed instance.

ALTER DATABASE WideWorldImporters
    SET AUTOMATIC_TUNING ( FORCE_LAST_GOOD_PLAN = ON)

ALTER DATABASE WideWorldImporters
    ADD FILE (NAME = 'data_17')

See also

CREATE DATABASE - Azure SQL Database
DATABASEPROPERTYEX
DROP DATABASE
SET TRANSACTION ISOLATION LEVEL
EVENTDATA
sp_configure
sp_spaceused
sys.databases
sys.database_files
sys.database_mirroring_witnesses sys.data_spaces
sys.filegroups
sys.master_files
System Databases

 

Azure SQL Data Warehouse

Overview

Modifies the name, maximum size, or service objective for a database.

Syntax

ALTER DATABASE database_name  

  MODIFY NAME = new_database_name  
| MODIFY ( <edition_option> [, ... n] )  

<edition_option> ::=   
      MAXSIZE = { 
            250 | 500 | 750 | 1024 | 5120 | 10240 | 20480 
          | 30720 | 40960 | 51200 | 61440 | 71680 | 81920 
          | 92160 | 102400 | 153600 | 204800 | 245760 
      } GB  
      | SERVICE_OBJECTIVE = { 
            'DW100' | 'DW200' | 'DW300' | 'DW400' | 'DW500' 
          | 'DW600' | 'DW1000' | 'DW1200' | 'DW1500' | 'DW2000' 
          | 'DW3000' | 'DW6000' | 'DW1000c' | 'DW1500c' | 'DW2000c' 
          | 'DW2500c' | 'DW3000c' | 'DW5000c' | 'DW6000c' | 'DW7500c' 
          | 'DW10000c' | 'DW15000c' | 'DW30000c'
      }  

Arguments

database_name
Specifies the name of the database to be modified.

MODIFY NAME = new_database_name
Renames the database with the name specified as new_database_name.

MAXSIZE
The default is 245,760 GB (240 TB).

Applies to: Optimized for Elasticity performance tier

The maximum allowable size for the database. The database cannot grow beyond MAXSIZE.

Applies to: Optimized for Compute performance tier

The maximum allowable size for rowstore data in the database. Data stored in rowstore tables, a columnstore index's deltastore, or a nonclustered index on a clustered columnstore index cannot grow beyond MAXSIZE. Data compressed into columnstore format does not have a size limit and is not constrained by MAXSIZE.

SERVICE_OBJECTIVE
Specifies the performance level. For more information about service objectives for SQL Data Warehouse, see Performance Tiers.

Permissions

Requires these permissions:

  • Server-level principal login (the one created by the provisioning process), or
  • Member of the dbmanager database role.

The owner of the database cannot alter the database unless the owner is a member of the dbmanager role.

General Remarks

The current database must be a different database than the one you are altering, therefore ALTER must be run while connected to the master database.

SQL Data Warehouse is set to COMPATIBILITY_LEVEL 130 and cannot be changed. For more details, see Improved Query Performance with Compatibility Level 130 in Azure SQL Database.

To decrease the size of a database, use DBCC SHRINKDATABASE.

Limitations and Restrictions

To run ALTER DATABASE, the database must be online and cannot be in a paused state.

The ALTER DATABASE statement must run in autocommit mode, which is the default transaction management mode. This is set in the connection settings.

The ALTER DATABASE statement cannot be part of a user-defined transaction.

You cannot change the database collation.

Examples

Before you run these examples, make sure the database you are altering is not the current database. The current database must be a different database than the one you are altering, therefore ALTER must be run while connected to the master database.

A. Change the name of the database

ALTER DATABASE AdventureWorks2012  
MODIFY NAME = Northwind;  

B. Change max size for the database

ALTER DATABASE dw1 MODIFY ( MAXSIZE=10240 GB );  

C. Change the performance level

ALTER DATABASE dw1 MODIFY ( SERVICE_OBJECTIVE= 'DW1200' );  

D. Change the max size and the performance level

ALTER DATABASE dw1 MODIFY ( MAXSIZE=10240 GB, SERVICE_OBJECTIVE= 'DW1200' );  

See Also

CREATE DATABASE (Azure SQL Data Warehouse) SQL Data Warehouse list of reference articles

 

SQL Parallel Data Warehouse

Overview

Modifies the maximum database size options for replicated tables, distributed tables, and the transaction log in Parallel Data Warehouse. Use this statement to manage disk space allocations for a database as it grows or shrinks in size. The article also describes syntax related to setting database options in Parallel Data Warehouse.

Syntax

-- Parallel Data Warehouse  
ALTER DATABASE database_name    
    SET ( <set_database_options>   | <db_encryption_option> )  
[;]  

<set_database_options> ::=   
{  
    AUTOGROW = { ON | OFF }  
    | REPLICATED_SIZE = size [GB]  
    | DISTRIBUTED_SIZE = size [GB]  
    | LOG_SIZE = size [GB]
    | SET AUTO_CREATE_STATISTICS { ON | OFF }
    | SET AUTO_UPDATE_STATISTICS { ON | OFF } 
    | SET AUTO_UPDATE_STATISTICS_ASYNC { ON | OFF }
}  

<db_encryption_option> ::=  
    ENCRYPTION { ON | OFF }  

Arguments

database_name
The name of the database to be modified. To display a list of databases on the appliance, use sys.databases (Transact-SQL).

AUTOGROW = { ON | OFF }
Updates the AUTOGROW option. When AUTOGROW is ON, Parallel Data Warehouse automatically increases the allocated space for replicated tables, distributed tables, and the transaction log as necessary to accommodate growth in storage requirements. When AUTOGROW is OFF, Parallel Data Warehouse returns an error if replicated tables, distributed tables, or the transaction log exceeds the maximum size setting.

REPLICATED_SIZE = size [GB]
Specifies the new maximum gigabytes per Compute node for storing all of the replicated tables in the database being altered. If you are planning for appliance storage space, you will need to multiply REPLICATED_SIZE by the number of Compute nodes in the appliance.

DISTRIBUTED_SIZE = size [GB]
Specifies the new maximum gigabytes per database for storing all of the distributed tables in the database being altered. The size is distributed across all of the Compute nodes in the appliance.

LOG_SIZE = size [GB]
Specifies the new maximum gigabytes per database for storing all of the transaction logs in the database being altered. The size is distributed across all of the Compute nodes in the appliance.

ENCRYPTION { ON | OFF }
Sets the database to be encrypted (ON) or not encrypted (OFF). Encryption can only be configured for Parallel Data Warehouse when sp_pdw_database_encryption has been set to 1. A database encryption key must be created before transparent data encryption can be configured. For more information about database encryption, see Transparent Data Encryption (TDE).

SET AUTO_CREATE_STATISTICS { ON | OFF } When the automatic create statistics option, AUTO_CREATE_STATISTICS, is ON, the Query Optimizer creates statistics on individual columns in the query predicate, as necessary, to improve cardinality estimates for the query plan. These single-column statistics are created on columns that do not already have a histogram in an existing statistics object.

Default is ON for new databases created after upgrading to AU7. The default is OFF for databases created prior to the upgrade.

For more information about statistics, see Statistics

SET AUTO_UPDATE_STATISTICS { ON | OFF } When the automatic update statistics option, AUTO_UPDATE_STATISTICS, is ON, the query optimizer determines when statistics might be out-of-date and then updates them when they are used by a query. Statistics become out-of-date after operations insert, update, delete, or merge change the data distribution in the table or indexed view. The query optimizer determines when statistics might be out-of-date by counting the number of data modifications since the last statistics update and comparing the number of modifications to a threshold. The threshold is based on the number of rows in the table or indexed view.

Default is ON for new databases created after upgrading to AU7. The default is OFF for databases created prior to the upgrade.

For more information about statistics, see Statistics.

SET AUTO_UPDATE_STATISTICS_ASYNC { ON | OFF } The asynchronous statistics update option, AUTO_UPDATE_STATISTICS_ASYNC, determines whether the Query Optimizer uses synchronous or asynchronous statistics updates. The AUTO_UPDATE_STATISTICS_ASYNC option applies to statistics objects created for indexes, single columns in query predicates, and statistics created with the CREATE STATISTICS statement.

Default is ON for new databases created after upgrading to AU7. The default is OFF for databases created prior to the upgrade.

For more information about statistics, see Statistics.

Permissions

Requires the ALTER permission on the database.

Error Messages

If auto-stats is disabled and you try to alter the statistics settings, PDW gives the error "This option is not supported in PDW." The system administrator can enable auto-stats by enabling the feature switch AutoStatsEnabled.

General Remarks

The values for REPLICATED_SIZE, DISTRIBUTED_SIZE, and LOG_SIZE can be greater than, equal to, or less than the current values for the database.

Limitations and Restrictions

Grow and shrink operations are approximate. The resulting actual sizes can vary from the size parameters.

Parallel Data Warehouse does not perform the ALTER DATABASE statement as an atomic operation. If the statement is aborted during execution, changes that have already occurred will remain.

The statistics settings only work if the administrator has enable auto-stats. If you are an administrator, use the feature switch AutoStatsEnabled to enable or disable auto-stats.

Locking Behavior

Takes a shared lock on the DATABASE object. You cannot alter a database that is in use by another user for reading or writing. This includes sessions that have issued a USE statement on the database.

Performance

Shrinking a database can take a large amount of time and system resources, depending on the size of the actual data within the database, and the amount of fragmentation on disk. For example, shrinking a database could take several hours or more.

Determining Encryption Progress

Use the following query to determine progress of database transparent data encryption as a percent:

WITH  
database_dek AS (  
    SELECT ISNULL(db_map.database_id, dek.database_id) AS database_id,  
        dek.encryption_state, dek.percent_complete,  
        dek.key_algorithm, dek.key_length, dek.encryptor_thumbprint,  
        type  
    FROM sys.dm_pdw_nodes_database_encryption_keys AS dek  
    INNER JOIN sys.pdw_nodes_pdw_physical_databases AS node_db_map  
        ON dek.database_id = node_db_map.database_id   
        AND dek.pdw_node_id = node_db_map.pdw_node_id  
    LEFT JOIN sys.pdw_database_mappings AS db_map  
        ON node_db_map .physical_name = db_map.physical_name  
    INNER JOIN sys.dm_pdw_nodes nodes  
        ON nodes.pdw_node_id = dek.pdw_node_id  
    WHERE dek.encryptor_thumbprint <> 0x  
),  
dek_percent_complete AS (  
    SELECT database_dek.database_id, AVG(database_dek.percent_complete) AS percent_complete  
    FROM database_dek  
    WHERE type = 'COMPUTE'  
    GROUP BY database_dek.database_id  
)  
SELECT DB_NAME( database_dek.database_id ) AS name,  
    database_dek.database_id,  
    ISNULL(  
       (SELECT TOP 1 dek_encryption_state.encryption_state  
        FROM database_dek AS dek_encryption_state  
        WHERE dek_encryption_state.database_id = database_dek.database_id  
        ORDER BY (CASE encryption_state  
            WHEN 3 THEN -1  
            ELSE encryption_state  
            END) DESC), 0)  
        AS encryption_state,  
dek_percent_complete.percent_complete,  
database_dek.key_algorithm, database_dek.key_length, database_dek.encryptor_thumbprint  
FROM database_dek  
INNER JOIN dek_percent_complete   
    ON dek_percent_complete.database_id = database_dek.database_id  
WHERE type = 'CONTROL';  

For a comprehensive example demonstrating all the steps in implementing TDE, see Transparent Data Encryption (TDE).

Examples: Parallel Data Warehouse

A. Altering the AUTOGROW setting

Set AUTOGROW to ON for database CustomerSales.

ALTER DATABASE CustomerSales  
    SET ( AUTOGROW = ON );  

B. Altering the maximum storage for replicated tables

The following example sets the replicated table storage limit to 1 GB for the database CustomerSales. This is the storage limit per Compute node.

ALTER DATABASE CustomerSales  
    SET ( REPLICATED_SIZE = 1 GB );  

C. Altering the maximum storage for distributed tables

The following example sets the distributed table storage limit to 1000 GB (one terabyte) for the database CustomerSales. This is the combined storage limit across the appliance for all of the Compute nodes, not the storage limit per Compute node.

ALTER DATABASE CustomerSales  
    SET ( DISTRIBUTED_SIZE = 1000 GB );  

D. Altering the maximum storage for the transaction log

The following example updates the database CustomerSales to have a maximum SQL Server transaction log size of 10 GB for the appliance.

ALTER DATABASE CustomerSales  
    SET ( LOG_SIZE = 10 GB );  

E. Check for current statistics values

The following query returns the current statistics values for all databases. The value 1 means the feature is on, and a 0 means the feature is off.

SELECT NAME,
    is_auto_create_stats_on,
    is_auto_update_stats_on,
    is_auto_update_stats_async_on
FROM sys.databases;

F. Enable auto-create and auto-update stats for a database

Use the following statement to enable create and update statistics automatically and asynchronously for database, CustomerSales. This creates and updates single-column statistics as necessary to create high quality query plans.

ALTER DATABASE CustomerSales
    SET AUTO_CREATE_STATISTICS ON;
ALTER DATABASE CustomerSales
    SET AUTO_UPDATE_STATISTICS ON; 
ALTER DATABASE CustomerSales
    SET AUTO_UPDATE_STATISTICS_ASYNC ON;

See Also

CREATE DATABASE (Parallel Data Warehouse)
DROP DATABASE (Transact-SQL)