In SQL Server, databases store their data and objects (such as tables, views, stored procedures, etc) in files. When you create a database using the default options, one data file and one log file are created. However, you’re not restricted to just one of each file. You can add data files (and log files) to a database at a later date if required.
This article contains examples of using T-SQL to add a data file to an existing database in SQL Server.
SQL Server databases store their data and objects in files. Each database has at least one data file (and a log file), but it’s not restricted to just one – it could have many data files. If you ever find yourself in the situation where you need to remove a data file from a database, you’ll need to empty that file first, before removing it.
But don’t worry, emptying a file doesn’t actually delete the data. It simply migrates the file’s data to other files within the same filegroup.
The examples below demonstrate how to empty a data file, then remove it from the database using Transact-SQL.
In SQL Server, when using Transact-SQL, reducing the size of a data file requires a different syntax to increasing it. To reduce a file size using T-SQL, use the DBCC SHRINKFILE command, and provide the name of the data file along with the size you’d like to reduce it to.
Below are examples of reducing the file size of a data file in SQL Server using T-SQL.
If you’re using the SQL Server Management Studio GUI, you can increase the size of a data file by right-clicking on the relevant database, selecting Properties, selecting Files under Database Properties, then increasing the value in the Initial Size (MB) column for the applicable data file.
If you’re using Transact-SQL however, you can increase the data file’s size by using the ALTER DATABASE statement with the MODIFY FILE argument. The following example demonstrates how to do this.
When using SQL Server, if you want to change the name of a database, you can do this by using a GUI (like SSMS) or by using Transact-SQL.
If using a GUI, you can right-click on the database name and click Rename to rename the database (you might need to set the database to single-user mode first).
If you’re doing this using T-SQL, the examples on this page should help you out.
In SQL Server, you can create, modify, and remove database objects using a graphical user interface (like using the GUI tools in SQL Server Management Studio), or you can use Transact-SQL to do the same tasks. In fact, the GUI tools actually use T-SQL behind the scenes to perform these tasks.
When using Transact-SQL, you can remove a column from a table by using the ALTER TABLE statement. This statement allows you to change a table’s definition by specifying exactly what changes you require. In our case, we require the removal of a column.
In database terms, a foreign key is a column that is linked to another table‘s primary key field in a relationship between two tables.
A foreign key is a type of constraint, and so if you want to create a foreign key in SQL Server, you’ll need to create a foreign key constraint.
This article demonstrates how to create a foreign key constraint in SQL Server, using Transact-SQL.
When you create a database table, you specify all columns along with their data types. Once created, there’s not normally any intention of changing these data types. After all, whoever designed the schema would have put a lot of thought into what data type each and every column should accept.
However, we all know that things can change. Despite our best efforts at trying to foresee every possible scenario that may hit our database, sometimes that’s not enough.
So what do we do if we need to use Transact-SQL to change the data type of a column in SQL Server?
We use the ALTER TABLE statement to change it of course.
In SQL Server, a constraint defines rules that data in a database must comply with. For example, you could have a UNIQUE constraint applied to a column to ensure that any value inserted into that column is unique (i.e. no other row shares the same value).
If later on you need to remove that constraint, here’s how to do it using Transact-SQL.
If you’re using SQL Server, and you want to use T-SQL to change the size of an existing column, this article can help.
By “changing the size of an existing column”, I mean changing the data size. For example, say you have a varchar(255) but you want to increase its size to varchar(500). Here’s what you need to do in that case.