Walkthrough: Adding and Changing a Database Diagram

Article
03/03/2023

Applies to: SQL Server

This walkthrough illustrates how to create and modify a database diagram and make changes to the database through the database diagrams component. You will see how to add tables to diagrams, create relationships between tables, create constraints and indexes on columns, and change the level of information you see for each table.

Prerequisites

In order to complete this walkthrough, you will need:

Access to SQL Server with the AdventureWorks2022 sample database
An account with database owner dbo privileges

Note

If you attempt to make changes when using an account without sufficient privileges to make changes to tables, then an error message appears.

Creating a Diagram

To create a new database diagram

On the View menu, click Object Explorer.
Open the Databases node and then open the AdventureWorks2022 node.
Right-click the Database Diagrams node and choose New Database Diagram.

If the database does not have objects necessary to create diagrams, the following message appears: This database does not have one or more of the support objects required to use database diagramming. Do you wish to create them? Choose Yes.

The Add Table dialog box appears.
Select AddressType (Person) and Address (Person) and click Add.

Two tables are added to the diagram.
Close the Add Table dialog box.

To view different column data

Right-click the Address table. On the shortcut menu, point to Table View, and then click Standard.

The table grid shows three columns: Column Name, Data Type, and Allow Nulls.
Right-click the Address table, click Table View and select Keys.

The table grid shows one column, with the table-column names. Only those columns participating in indexes appear.

Creating New Tables

To create tables within Diagram Designer

Right-click the Diagram Designer outside the existing tables and choose New Table.
In the Choose Name dialog box, click OK to accept the default name Table1.

A new table grid appears with three columns: Column Name, Data Type, and Allow Nulls.
Add the following information to Table1:

Column Name Data Type Allow Nulls

T1col1 int checked

T1col2 varchar(50) checked

T1col3 float checked
Right-click T1col1 and select Set Primary Key.

A key icon will appear beside the column name.
From the File menu, click Save Diagram1.
In the Choose Name dialog box, click OK to accept the default name Diagram1.
The Save dialog box appears with a message that Table1 will be saved to the database. Click Yes.

Column Name	Data Type	Allow Nulls
T1col1	int	checked
T1col2	varchar(50)	checked
T1col3	float	checked

Modifying Table Structure

You can add check constraints and make relationships between tables in Diagram Designer.

To create check constraints

In Table1, right-click the T1col3 row and choose Check Constraints.

The Check Constraints dialog box appears.
Click Add.

A new constraint appears in the Selected Check Constraint list, with the default name CK_Table1.
Select the Expression row in the grid and click the ellipsis button.

The Check Constraint Expression dialog box appears.
Type T1col3 > 5 and click OK.

Table1 now has a constraint that all values entered into T1col3 must be greater than 5.
Click Close.

To create relationships between tables

Create a new table in Diagram designer named Table2 with the following columns:

Column Name Data Type Allow Nulls

T2col1 int not checked

T2col2 varchar(50) checked

T2col3 xml checked

Note

The columns on the primary key side of a foreign key relationship must participate in either a Primary Key or a Unique Constraint.
Drag T2col1 to T1col1.

Two dialog boxes appear: Foreign Key Relationship in the background and Tables and Columns in the foreground.
Click OK to save the new relationship.
Click OK again.

Column Name	Data Type	Allow Nulls
T2col1	int	not checked
T2col2	varchar(50)	checked
T2col3	xml	checked

Creating Indexes

You can create indexes on most types of data, including XML.

To create a standard index

Right-click Table1 and choose Indexes/Keys.

The Indexes/Keys dialog box appears.
Click Add.

A new index appears in the Selected Primary/Unique Key or Index list, with a default name similar to IX_Table1.
Select the Columns row and click the ellipsis button.

The Index Columns dialog box appears.
Click the drop-down arrow under Column Name and select T1col2.

Note

You may add additional columns to this index by selecting the cell below T1col2 and choosing another column name.
Click OK to save this index.
Click Close in the Indexes/Keys dialog box.

To create an XML index

Right-click T2col1 and choose Set Primary Key.

Note

Adding an XML index requires that another column in the table be set as a clustered primary key.
Right-click the T2col3 row in Table2 and select XML Indexes.

The XML Indexes dialog box appears.
Click Add.

An XML index with default values will be added to the Selected XML Index list.
Click Close.

Note

XML indexes are created per-column. The first XML index is primary; any additional indexes are secondary.

Saving the Diagram

All of the changes you make to a diagram are not posted to the database until you save it. If there are problems or conflicts, a dialog box appears with more information.

To save a database diagram

On the File menu, select Save Diagram1.

The Save dialog box appears. If Warn about Tables Affected is selected, information about new or changed tables is listed.
Click OK.
If any errors occurred, the Post-Save Notifications dialog box appears with the errors and their causes. Fix the errors and save the diagram again.

Next Steps

This is a basic diagram with just two existing and two new tables, but it illustrates the potential for diagramming an existing database or creating a new schema visually. Suggestions for more exploration include:

Create new diagrams containing groups of related tables
Customize the amount of information shown for each table
Change the layout and add annotations
Copy the diagram to a bitmap