While doing 'one of ' lookups of a primary key where the primary key is a guid (most used query using a primary key), using a fragmented index and unfragmented data pages will likely still be more efficient than using a fragmented data pages where the guid is clustered primary key. Introduction to SQL Server PRIMARY KEY constraint. A primary key is a column or a group of columns that uniquely identifies each row in a table. You create a primary key for a table by using the PRIMARY KEY constraint. If the primary key consists of only one column, you can define use PRIMARY KEY constraint as a column constraint.

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APPLIES TO: SQL Server 2016 and later Azure SQL Database Azure Synapse Analytics (SQL DW) Parallel Data Warehouse

You can modify a primary key in SQL Server 2019 (15.x) by using SQL Server Management Studio or Transact-SQL. You can modify the primary key of a table by changing the column order, index name, clustered option, or fill factor.

In This Topic

• Generate ssh key ubuntu for github. Before you begin:

• To modify a primary key, using:

Before You Begin

Security

Permissions

Requires ALTER permission on the table.

Generating Primary Key Column Sql Pdf

Using SQL Server Management Studio

To modify a primary key

1. Open the Table Designer for the table whose primary key you want to modify, right-click in the Table Designer, and choose Indexes/Keys from the shortcut menu.

2. In the Indexes/Keys dialog box, select the primary key index from the Selected Primary/Unique Key or Index list.

3. Complete an action from the following table:

   To	Follow these steps
   Rename the primary key	Type a new name in the Name box. Make sure that your new name does not duplicate a name in the Selected Primary/Unique Key or Index list.
   Set the clustered option	To create a clustered index for the primary key, select Create as CLUSTERED, and select the option from the drop-down list box. Only one clustered index can exist per table. If this option is not available for your index, you must first clear this setting on the existing clustered index. If this option is not selected, a unique nonclustered index is created.
   Define a fill factor	Expand the Fill Specification category and type an integer from 0 to 100 in the Fill factor box. For more information about fill factors and their uses, see Specify Fill Factor for an Index.
   Change the column order	Select Columns, and then click the ellipses (..) to the right of the property. In the Index Columns dialog box, remove the columns from the primary key. Then add the columns back in the order you want. To remove a column from the key, simply remove the column name from the Column name list.

4. On the File menu, click Savetable name.

Find Primary Key Sql

Using Transact-SQL

To modify a primary key

Insert Primary Key Sql

/mafia-2-cd-key-steam-generator.html. To modify a PRIMARY KEY constraint using Transact-SQL, you must first delete the existing PRIMARY KEY constraint and then re-create it with the new definition. For more information, see Delete Primary Keys and Create Primary Keys.