1
vote
1answer
76 views

Update new column with value from old columns for all the rows

I've got an odd db design in place that was here when I got on my new work space. We have a column named params which contains some string data which appears that it belongs in more than one column, ...
6
votes
1answer
11k views

What happens when you modify (reduce) a column's length?

Lets say I have two columns of type NUMBER (without precision, and scale) and VARCHAR(300). I saw that these columns are way too large for my data, so I want to modify them to NUMBER(11) and ...
3
votes
2answers
749 views

php/mysql database redesign and migration: changing databases to tables

I wrongly designed my application to have one database to each user. each user had 3 similar tables. I now want to have one database and 3 tables only; where i will use the database name in the old ...
2
votes
2answers
617 views

Logical schema development and migration tool for different physical schema available including triggers and stored procedures?

We are planning to support for our application another rdbms (oracle). At the moment we are design our database schema with the MySQL-Workbench. For every new database version we have schema ...
2
votes
3answers
812 views

Migrating from ntext to NVARCHAR(MAX)

I have table with the columns of type ntext.And for some peculiar reasons, client want to migrate the column type to NVARCHAR(MAX). While doing so , what all potential threat should i be careful ...