In SQL Server, there are two types of table partitions: Horizontal and vertical. In this article, we will show you what is Horizontal Table Partitioning in SQL Server and how to create it with example.
SQL Horizontal Table Partition: Dividing table into multiple tables is called Horizontal Table Partition. It is helpful to organize data for quick access. For SQL Server Table Partitioning example, dividing the Sales table into Monthly partition, or Quarterly partition will help the end-user to select records quickly.
Remember, all the partition tables contain the same number of columns.
Before we start to create Table Partitioning in SQL Server, let me show you the list of databases that are available in our local file system.
From the below screenshot you can see the available databases in our server
For this SQL demonstration, we created a new database called PartSample
Now you can see our newly created database PartSample in our file system
How to create Table Partitioning in SQL Server?
In this example, we will create a table partition in SQL Server to store data in month-wise. I mean, orders or sales in each month will store in separate filegroups (files with ndf extension).
To achieve the same, we have to create 12 separate file groups for 12 months from January to December. To create a filegroup, we have to use Alter Database command
-- Table Partitioning in SQL Server ALTER DATABASE PartSample ADD FILEGROUP January GO ALTER DATABASE PartSample ADD FILEGROUP February GO ALTER DATABASE PartSample ADD FILEGROUP March GO ALTER DATABASE PartSample ADD FILEGROUP April GO ALTER DATABASE PartSample ADD FILEGROUP May GO ALTER DATABASE PartSample ADD FILEGROUP June GO ALTER DATABASE PartSample ADD FILEGROUP July GO ALTER DATABASE PartSample ADD FILEGROUP August GO ALTER DATABASE PartSample ADD FILEGROUP September GO ALTER DATABASE PartSample ADD FILEGROUP October GO ALTER DATABASE PartSample ADD FILEGROUP November GO ALTER DATABASE PartSample ADD FILEGROUP December GO
OUTPUT
Get FileGroups – Table Partitioning in SQL Server
Use below query to check or see the list of file groups available in this database
-- Table Partitioning in SQL Server USE PartSample GO SELECT * FROM Sys.filegroups
OUTPUT
You can also use the below query to return file group names
-- Table Partitioning in SQL Server USE PartSample GO SELECT name AS [File Group Name] FROM Sys.filegroups WHERE type = 'FG'
OUTPUT
Add ndf files to File Groups – Table Partitioning in Sql Server
Once you created the filegroups, you have to add or assign or create ndf files. Below query will add ndf file to January File group
-- Table Partitioning in SQL Server ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartJan], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartJan.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [January]
OUTPUT
Use below query to add ndf files for the remaining 11 month. Remember, this is the physical location where monthly data is going to store.
-- Table Partitioning in SQL Server -- Adding ndf for February File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartFeb], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartFeb.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [February] -- Adding ndf for March File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartMarch], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartMarch.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [March] -- Adding ndf for April File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartApril], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartApril.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [April] /-- Adding ndf for May File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartMay], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartMay.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [May] -- Adding ndf for June File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartJune], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartJune.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [June] -- Adding ndf for July File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartJuly], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartJuly.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [July] -- Adding ndf for August File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartAug], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartAug.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [August] -- Adding ndf for September File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartSept], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartSept.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [September] -- Adding ndf for October File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartOct], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartOct.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [October] -- Adding ndf for November File Group ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartNov], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartNov.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [November] -- File Group for December ALTER DATABASE [PartSample] ADD FILE ( NAME = [PartDec], FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQL\DATA\PartDec.ndf', SIZE = 5080 KB, MAXSIZE = UNLIMITED, FILEGROWTH = 2040 KB ) TO FILEGROUP [December]
OUTPUT
Let me open my file system.
From the below screenshot you can see, ndf files has created for each file group
View File groups and respective ndf files – SQL Table partition
Use sys.database_files to get information about file groups and their physical locations.
-- Table Partitioning in SQL Server USE PartSample GO SELECT * FROM sys.database_files
OUTPUT
You can also use more specific columns in the select statement
-- Table Partitioning in SQL Server USE PartSample GO SELECT name AS [Partition Name], physical_name AS [File Path] FROM sys.database_files -- WHERE type_desc = 'ROWS'
OUTPUT
Create Partition Function – Table Partitioning in Sql Server
This function will map the rows from the original table (I mean, partition table) to the partition tables. For this, the SQL partition function will use one column to identify the filegroup.
The below function will map the original table to file groups based on each month. This function compares the insert date value and map to one of the partitions based on the values we specified within the brackets ().
-- Table Partitioning in SQL Server USE PartSample GO CREATE PARTITION FUNCTION [MonthlyPartition] (datetime) AS RANGE RIGHT FOR VALUES ('20180201', '20180301', '20180401', '20180501', '20180601', '20180701', '20180801', '20180901', '20181001', '20181101', '20181201');
OUTPUT
Create Partition Scheme – Table Partitioning in Sql Server
This will map the partition tables with the file groups. Below scheme will map 20180201 to February etc
-- Table Partitioning in SQL Server USE PartSample GO CREATE PARTITION SCHEME MonthWisePartition AS PARTITION MonthlyPartition TO (January, February, March, April, May, June, July, August, September, October, November, December );
OUTPUT
Create a Table with Table Partitioning
Let me create a table using the newly created SQL Server Table partitioning schema. I suggest you refer Create table, and Identity Column to understand the below code.
-- Table Partitioning in SQL Server USE [PartSample] GO CREATE TABLE [dbo].[SQL Insert]( [EmpID] [int] IDENTITY(1,1) NOT NULL, [FirstName] [nvarchar](255) NULL, [LastName] [nvarchar](255) NULL, [Occupation] [nvarchar](255) NULL, [YearlyIncome] [float] NULL, [Sales] [float] NULL, [InsertDate] [datetime] NULL ) ON MonthWisePartition (InsertDate);
OUTPUT
Let me insert few records into the newly created table. Please refer Insert Statement article to understand the insert operations
-- Table Partitioning in SQL Server USE [PartSample] GO INSERT INTO [dbo].[SQL Insert] VALUES ('Imran', 'Khan', 'Skilled Professional', 15900, 100, GETDATE()) ,('Doe', 'Lara', 'Management', 15000, 60, GETDATE()) ,('Ramesh', 'Kumar', 'Professional', 65000, 630, DATEADD(month, 1, GETDATE()))
OUTPUT
You can see those records
Next, we inserted few more records with different dates. Notice, we used DATEADD function to add or delete months from current date.
-- Table Partitioning in SQL Server USE [PartSample] GO INSERT INTO [dbo].[SQL Insert] VALUES ('Tutorial', 'Gateway', 'Masters', 14500, 200, DATEADD(month, 4, GETDATE())) ,('Joe', 'Root', 'Management', 10000, 160, DATEADD(month, 3, GETDATE())) ,('SQL', 'Tutorial', 'Management', 15000, 120, DATEADD(month, 2, GETDATE())) ,('Jhon', 'Wick', 'Software Sales', 21000, 1160, DATEADD(month, -7, GETDATE())) ,('Steve', 'Smith', 'App Sale', 13000, 2160, DATEADD(month, -6, GETDATE())) ,('Kishore', 'Kumar', 'Admin', 120500, 310, DATEADD(month, -5, GETDATE())) ,('Demi', 'Lovato', 'Professional', 193000, 1260, DATEADD(month, -4, GETDATE())) ,('Madison', 'De', 'Management', 90000, 1090, DATEADD(month, -3, GETDATE())) ,('Wang', 'Chung', 'Software Sale', 15000, 1560, DATEADD(month, -2, GETDATE())) ,('Dave', 'Jhones', 'Professional', 55000, 630, DATEADD(month, -1, GETDATE()))
OUTPUT
Fro the below screenshot you can see all the records. If you observe the insert dates, each month has one record, and August had 2 records
View Records in Table Partitioning
Use below query to see the total number of rows per file group or partition
-- Table Partitioning in SQL Server SELECT partition_id AS ID, partition_number AS [Partition Number], rows AS [Number of Rows] FROM sys.partitions AS part WHERE OBJECT_NAME(OBJECT_ID) = 'SQl Insert'
OUTPUT
You can use below query to see the File Group name along with total number of rows in the SQL table partitioning.
-- Table Partitioning in SQL Server USE PartSample SELECT part.partition_number AS [Partition Number], fle.name AS [Partition Name], part.rows AS [Number of Rows] FROM sys.partitions AS part JOIN SYS.destination_data_spaces AS dest ON part.partition_number = dest.destination_id JOIN sys.filegroups AS fle ON dest.data_space_id = fle.data_space_id WHERE OBJECT_NAME(OBJECT_ID) = 'SQL Insert'
OUTPUT
TIP: Please refer Create Table Partition article to understand the spruces of creating partition using SQL Management Studio.