Using the OUTPUT Clause: A simple data archiving example

Using the OUTPUT Clause: A simple data archiving example

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The OUTPUT Clause in T-SQL as described in MSDN SQL Server BOL, “returns information from, or expressions based on, each row affected by an INSERT, UPDATE, DELETE, or MERGE statement.

The functionality provided by the OUTPUT clause is very powerful and can be used in many scenarios. One such a scenario is Data Archiving.

Consider the following example based on which there is a “CustomerData” table containing customer IDs and status codes indidicating whether a customer is Active or Inactive.

A data archiving scenario would be to archive all the customers having the status “INACTIVE”.

For this example I am going to use two tables called “CustomerData” and “CustomerArchive“.

OK, let’s see some code!


–Creates the schema
CREATE SCHEMA Test
GO


–Creates the data table for customers
CREATE TABLE Test.CustomerData
(
ID int IDENTITY(1,1) NOT NULL,
StatusCode VARCHAR(10) NOT NULL
)
GO


–Creates the data table for customers archive
CREATE TABLE Test.CustomerArchive
(
ID int NOT NULL,
StatusCode VARCHAR(10) NOT NULL
)
GO


–Populates data table with some sample data (Using Row Constructors)
INSERT INTO Test.CustomerData (StatusCode)
VALUES    (‘ACTIVE’),
        (‘ACTIVE’),
        (‘INACTIVE’),
        (‘ACTIVE’),
        (‘ACTIVE’),
        (‘INACTIVE’),
        (‘ACTIVE’),
        (‘INACTIVE’),
        (‘ACTIVE’),
        (‘ACTIVE’)


Now, let’s check out the contents of the two tables:

CustomerData

CustomerArchive

Now, let’s archive the CustomersData table using the OUTPUT clause in the below query:

–Archive inactive customers and store the records in the “CustomerArchive” table
DELETE FROM Test.CustomerData
OUTPUT DELETED.* INTO Test.CustomerArchive
WHERE StatusCode=’INACTIVE’

CustomerData

CustomerArchive

As you can see from the above results, with just a single T-SQL statement, we managed to delete the desired data from the CustomerData table and also archive it into the CustomerArchive table.

The above scenario was just a simple example on how data archiving can be performed using the OUTPUT clause in SQL Server. You can build more complex data archiving logic using the OUTPUT clause as you can also use the INSERTED keyword and perform multiple joins in the query which uses the OUTPUT clause.

Note: Always be careful when deleting data! Always keep a backup of your data.


Recommended eBooks on SQL Server:

Tuning SQL Server: eBook by SQL Server MVP Artemakis Artemiou
Tuning SQL Server: eBook by SQL Server MVP Artemakis Artemiou
Administering SQL Server: eBook by SQL Server MVP Artemakis Artemiou
Administering SQL Server: eBook by SQL Server MVP Artemakis Artemiou
Artemakis Artemiou
Artemakis Artemiou is a Senior SQL Server Architect, Author, Software Developer and a Microsoft Data Platform MVP. He has over 15 years of experience in the IT industry in various roles. Among other, via his initiative SQLEBooks.com, Artemakis authors and publishes eBooks on different topics on SQL Server. Artemakis currently serves as the President of the Cyprus .NET User Group (CDNUG) and the International .NET Association Country Leader for Cyprus (INETA). Additionally he is the founder of the SQLArtBits initiative that aims to provide the technical community with simple, yet powerful and high-quality SQL Server tools. Currently, the highlights of these tools are DBA Security Advisor and In-Memory OLTP Simulator. Artemakis's official website can be found at aartemiou.com. Artemakis's blogs can be found at: SQLNetHub.com and TechHowTos.com.