Primary & Foreign Keys in pgAdmin

Solution 1:

Yes, there is a way to add Primary & Foreign Keys in pgAdmin.

Tested in pgAdmin III Ver.1.16.1 (Windows 7)

1. Select the table you want
2. Ctrl+Alt+Enter or right-click / Properties
3. Select "Constraints" tab
4. At the left-bottom side of the form you will see the option "Primary Key"
5. Click add
6. Select "Columns" tab
7. Select the column you want as a key
8. Click add

And you are all set.

You can fill more things if you want, but now you know how to get there.

Solution 2:

There is no option in pgAdmin to add a column to an existing table and make it the primary key at the same time, because this is hardly possible.

A primary key column needs to hold unique non-null values. Upon adding a column to an existing table, it holds NULL values. So you have to enter unique values before you can add a UNIQUE or PRIMARY KEY constraint.

There is an exception to that rule, though: If you add a serial column, unique values are inserted automatically. In this case, you can also define it PRIMARY KEY right away:

ALTER TABLE student ADD COLUMN student_number serial PRIMARY KEY;

This works in PostgreSQL 9.1. I am not sure it does in older versions, too.

pgAdmin does not incorporate this special case for serial columns in the "New column..." dialog at this time (version 1.14).

Solution 3:

In Pgadmin3,

1. Go to table which you want to add the PK or FK and right click and choose properties.

2. Go to constraints tab.

3. Choose Primary Key or Foreign Key in drop down list which beside of Add button.

4. And than click on add button.

5. Go to columns tab.

6. Choose the column name in drop down list ,which you want to add .

7. Click add button.

8. Click Ok button.

   Hope it will helpful for you !