Solved

Creating a Primary Key after table created

Posted on 2003-11-28
1
3,548 Views
Last Modified: 2008-01-16
I am using PHPMyAdmin to administer my database and I am trying to add a primary key.  The primary key did not come over in the conversion from Access to MySQL for some reason (used Access2MySQL program).  When I attempt to add the primary key from PHPMyAdmin I get the error:

"#1171 - All parts of a PRIMARY KEY must be NOT NULL;  If you need NULL in a key, use UNIQUE instead"

The problem is that there are no rows that have a null value in the column I am trying to declare as the primary key.  When I do a SQL query that reads:

SELECT *
FROM employee
WHERE employee_id is NULL;

I get 0 rows returned.  Anyone have any suggestions?

Thanks.

Jayce

PS.  The version of MySQL I am using is 3.23.53-max-nt ... if that makes any difference
0
Comment
Question by:llcooljayce
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
1 Comment
 
LVL 3

Accepted Solution

by:
cwp earned 50 total points
ID: 9839602
Using primary keys requires the column to have the "NOT NULL" attribute set (or the "Null" column doesn't have the Yes word in "DESCRIBE employee").

I don't use PHPMyAdmin, so I don't know where, if it is possible, you can set the column attributes, but in SQL code, you'll need to redefine the column:

ALTER TABLE employee CHANGE COLUMN employee_id employee_id INT UNSIGNED NOT NULL;

You should change the "INT UNSIGNED" part to whatever the data type is for the employee_id.
0

Featured Post

Learn how to optimize MySQL for your business need

With the increasing importance of apps & networks in both business & personal interconnections, perfor. has become one of the key metrics of successful communication. This ebook is a hands-on business-case-driven guide to understanding MySQL query parameter tuning & database perf

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Popularity Can Be Measured Sometimes we deal with questions of popularity, and we need a way to collect opinions from our clients.  This article shows a simple teaching example of how we might elect a favorite color by letting our clients vote for …
This article shows the steps required to install WordPress on Azure. Web Apps, Mobile Apps, API Apps, or Functions, in Azure all these run in an App Service plan. WordPress is no exception and requires an App Service Plan and Database to install
In this video, viewers will be given step by step instructions on adjusting mouse, pointer and cursor visibility in Microsoft Windows 10. The video seeks to educate those who are struggling with the new Windows 10 Graphical User Interface. Change Cu…
Monitoring a network: why having a policy is the best policy? Michael Kulchisky, MCSE, MCSA, MCP, VTSP, VSP, CCSP outlines the enormous benefits of having a policy-based approach when monitoring medium and large networks. Software utilized in this v…

636 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question