February 12, 2016 at 9:37 am
Comments posted to this topic are about the item NULLs to Not NULLs
Igor Micev,My blog: www.igormicev.com
February 22, 2016 at 8:11 am
Why would I want to change a Null to a Not Null. A little explanation of the script would be nice. What problem is it trying to solve?
February 22, 2016 at 8:23 am
Good notice, and I saw that I haven't put all what I wanted with this script as an explanation.
I have found many columns in many tables of many databases that are defined to allow NULLs but have non NULL values. That's actually an experience of working with constraints and when I got to understand what does mean to have a not nullable columns against nullabes in tables. The difference is big. This post (https://www.simple-talk.com/sql/t-sql-programming/how-to-get-nulls-horribly-wrong-in-sql-server/) gives you a wide window on this importance.
Script finds char types columns defined to allow NULL values but have non NULL values and generates the ALTER statements for the changes.
And of course you have to check whether all generated ALTER statements will pass to be executed after checking with the other programmable parties that use the database.
In my databases I found out columns without null values but defined to allow nulls. The data is being used for a couple of years, and no nulls are inserted. After a short talk with the application developers a decision felt down that we go with altering those columns.
P.S. I inherited the databases' development.
Igor Micev,My blog: www.igormicev.com
February 22, 2016 at 8:42 am
Thanks for the quick response. I will have to look at my tables and the constraints on them.
February 22, 2016 at 10:36 am
I think you should get check all NULLable columns for a given table in a single pass. It could hurt severely hurt performance to have to scan the same table multiple times.
SQL DBA,SQL Server MVP(07, 08, 09) "It's a dog-eat-dog world, and I'm wearing Milk-Bone underwear." "Norm", on "Cheers". Also from "Cheers", from "Carla": "You need to know 3 things about Tortelli men: Tortelli men draw women like flies; Tortelli men treat women like flies; Tortelli men's brains are in their flies".
February 22, 2016 at 4:18 pm
ScottPletcher (2/22/2016)
I think you should get check all NULLable columns for a given table in a single pass. It could hurt severely hurt performance to have to scan the same table multiple times.
Yes, it's possible for improvements. That's why the discussion is for. Thanks.
Igor Micev,My blog: www.igormicev.com
March 9, 2016 at 4:41 pm
We've made creation mistakes, allowing nulls when we really want the data constrained.
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