Partitioned View Definition

Partitioned views are views defined by using UNION ALL on member tables that have the same structure but are stored separately as multiple tables in the same SQL Server instance or in an autonomous group of SQL Server Server instances called a federated database Server.

The preferred way to partition a server’s local data is through partitioned tables.

Instead of using SSMS database management tools to create partitioned views, you can use transact-SQL scripts to create partitioned views.

Conditions for creating partitioned views

1. Select List

All columns in the member table should be selected from the list of columns defined by the view. Columns at the same ordinal position in each Select List should be of the same type, including collation. It is not sufficient that a column belongs only to an implicitly convertible type, such as UNION in general. The constraint should be defined as follows: any specified value of, can satisfy at most one C1,… Cn constraints, so that the constraints form a set of unjoined or non-overlapping intervals. Columns that define unjoined constraints are called partitioned columns. Note that partitioned columns may have different names in the underlying table. Constraints should be enabled and trusted so that they satisfy the conditions above for partitioned columns. If the CONSTRAINT is disabled, re-enable CONSTRAINT checking using the CHECK CONSTRAINT constraint_name option of ALTER TABLE and validate it using the WITH CHECK option. You cannot use the same column more than once in a selection list. 2, partition column

The partitioned column is part of the PRIMARY KEY of the table.

A partitioned column cannot be a computed, identity, default, or TIMESTAMP column.

If there are more than one constraint on the same column in the member table, the database engine ignores all constraints and does not consider them when determining whether the view is a partitioned view. To satisfy the conditions for a partitioned view, there should be only one partition constraint on the partitioned column.

There is no limit to the updatability of partitioned columns.

Mysql > alter table T1; , Tn

A table can be a local table or a table in another machine running SQL Server that is referenced by a four-part name or based on the OPENDATASOURCE or OPENROWSET name. The OPENDATASOURCE and OPENROWSET syntax can specify table names, but not directly passing queries. For more information, see OPENDATASOURCE (Transact-SQL) and OPENROWSET (Transact-SQL).

If one or more member tables are remote, the view is called a “distributed partitioned view” and additional conditions apply. They will be explained later in this section.

In a set of tables combined with the UNION ALL statement, the same table cannot appear twice.

Member tables cannot create indexes for computed columns in the table.

Member tables should have all PRIMARY KEY constraints on columns with the same number.

All member tables in the view should have the same ANSI population Settings. This can be SET using the user options option in sp_configure or the SET statement.

Create a partitioned view using the T-SQL script

Grammar:

Declare database references

Use database name;

go

Determine whether a partitioned view exists and delete it if it does

If exists(select * from sys.views where name= view name)

Drop view View name;

go

Create a partition view

create

view

— The name of the schema to which the view belongs.

–[schema_name][.]

[dbo]. View name

— The name used by the columns in the view. Column names are needed only when a column is derived from an arithmetic expression, function, or constant; Two or more columns may have the same name (usually due to joins); The specified name of a column in a view is different from the name of the column from which it derives. You can also assign column names in the SELECT statement.

If column is not specified, the view column gets the same name as the column in the SELECT statement.

(Column name, column name,…….)

[with]

— Applicable to SQL Server 2008 to SQL Server 2017 and Azure SQL Database

— Encrypt entries in the sys.syscomments table that contain the text of the CREATE VIEW statement. Use WITH ENCRYPTION to prevent views from being published during SQL Server replication.

[encryption][,]

When a query request that references a view is specified to browse schema metadata, the SQL Server instance returns metadata information about the view to the DB-Library, ODBC, and OLE DB API, but not the base table metadata information.

Browse mode metadata is additional metadata returned by SQL Server instances to these client apis. If you use this metadata, the client API can implement updatable client cursors. The metadata for the browse schema contains information about the base table to which the columns in the result set belong.

For views created using VIEW_METADATA, browse mode metadata returns the view name, not the base table name, when describing the columns in the view within the result set.

When a view is created WITH VIEW_METADATA, all columns OF the view (except timestamp columns) can be updated if the view has an INSTEAD OF INSERT or INSTEAD OF UPDATE trigger. For more information about updatable views, see Notes.

[view_metadata]

as

select_statement

go

Example:

Declare database references

use testss;

go

Determine whether a partitioned view exists and delete it if it does

if exists(select * from sys.views where name=’partitionview’)

drop view partitionview;

go

Create a partition view

create

view

— The name of the schema to which the view belongs.

–[schema_name][.]

dbo.partitionview

— The name used by the columns in the view. Column names are needed only when a column is derived from an arithmetic expression, function, or constant; Two or more columns may have the same name (usually due to joins); The specified name of a column in a view is different from the name of the column from which it derives. You can also assign column names in the SELECT statement.

If column is not specified, the view column gets the same name as the column in the SELECT statement.

(name,sex)

with

— Applicable to SQL Server 2008 to SQL Server 2017 and Azure SQL Database

— Encrypt entries in the sys.syscomments table that contain the text of the CREATE VIEW statement. Use WITH ENCRYPTION to prevent views from being published during SQL Server replication.

encryption,

When a query request that references a view is specified to browse schema metadata, the SQL Server instance returns metadata information about the view to the DB-Library, ODBC, and OLE DB API, but not the base table metadata information.

Browse mode metadata is additional metadata returned by SQL Server instances to these client apis. If you use this metadata, the client API can implement updatable client cursors. The metadata for the browse schema contains information about the base table to which the columns in the result set belong.

For views created using VIEW_METADATA, browse mode metadata returns the view name, not the base table name, when describing the columns in the view within the result set.

When a view is created WITH VIEW_METADATA, all columns OF the view (except timestamp columns) can be updated if the view has an INSTEAD OF INSERT or INSTEAD OF UPDATE trigger. For more information about updatable views, see Notes.

view_metadata

as

— Avoid using * when querying, Select a.name, a.name from [testss].[dbo]. Test1 as a union all select B.name, b.name from [Tests].[dbo].test1 as b

go

Example results:

Partition view creation result.

Partition view usage results.