Read This Before You Redesign Your Database!

Read This Before You Redesign Your Database!

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As company company evolves, the tricks that they store and technique also changes and meaning the underlying database constructions which have been holding effectively for decades calls for to be modified as effectively. This are even more evolved when you have remodel an "in use" system.

Here is a steadily representative on what calls for to be achieved:

Step 1: Draw the shape of the brand new database on Paper Based on the brand new company company requirements, you favor to draw the shape of the brand new database on paper. We primarily use MS Access at this stage by way of the assertion it has a acquired a "Documenter" tool which generates a genuine professional output in a comparatively at once time.

Step 2: Analyze Existing Scripts / Code
Now you favor to envision the existing code to see how they'll be utilizing the current database shape and the way this usage will distinction in response to the revised shape. For instance, while you're attempting to split a lengthy table into two separate tables, then all past "Select *" queries on that table will be productive. Thus, all the existing code will must be rewritten.

Step three: Create a migration plan
You favor to create a migration plan. Leaving the tech stuff apart, this really means how you will cross the realize-how from the classic realize-how into the brand new database. For this you will have a write a script of some kind. This stage is especially very important by way of the assertion you might potentially should adjust your new database. For instance: If in the classic database you have users table which had a name column. Now, if the revised database has firstname, middlename and lastname column then I can wager your database remodel dreams will end here as you cant migrate the realize-how between all and sundry versions unless your plan includes manual typing.

Step four: Create the brand new database
Now you get to design the brand new database shape as it must be implemented unless you have achieved in the very first step itself.

Step 5: Test the Migration Plan with a Demo Script
You now favor to research the migration plan on a sub-set of "classic" database to make exact that the realize-how might be migrated as you planned.

Step 6: Adjust the code
Now its time to edit the code! You favor to go line by line and distinction all queries which are affected by the revised design.

Step 7: Perform the Migration
The day you have been waiting for has finally arrived; you get to hold out the migration meaning you upload the brand new code and execute the migration script.

Last Step: Test
All said and achieved, achieved forget to research the entire system once over again to make exact that theme matters are working as expected.
Of course, you need to not ever play with the live database. With all the ones GUI apparatus obtainable available in the market, its real tempting and easy to make changes on the live system. Always paintings on a backup replica and carry out the migration on bodily system once the dummy system has been examined as a matter of assertion.

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