Developers modify a primary key when he/she wants to change the column order, index name, clustered option, or fill factor. In this case Developers follow the next steps:
1. Open the Table Designer for the table whose primary key they 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:
|Primary key is renamed
|Type a new name in the Name box. Make sure that their new name does not duplicate a name in the Selected Primary/Unique Key or Index list.|
|Clustered option is set||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 their index, they must first clear this setting on the existing clustered index.|
|A fill factor is defined||Expand the Fill Specification category and types an integer from 0 to 100 in the Fill factor box. The fill factor value determines the percentage of space on each leaf level page to be filled with data, therefore reserving a percentage of free space for future growth. For example, specifying a fill factor value of 80 means that 20 percent of each leaf-level page will be left empty providing space for index expansion as data is added to the underlying table.|
|The column order is changed||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 they want. To remove a column from the key, simply remove the column name from the Column name list.|
The primary key is updated in the database when developers save their table.