Lately I've been busy working with databases for my spare time projects. I imported a huge dump of data into the db via CSV import, but forgot to add an Unique Id Column (Primary Key). Not willing to do the whole import job again, I searched for a solution online to add an Id column to an existing table without any hassle, and found one:
ALTER TABLE `tablename` ADD COLUMN `id` INT AUTO_INCREMENT UNIQUE FIRST;
Another trick was the CSV import itself. Pretty much all data can be inserted into MySQL by using an CSV export, in my case, from an ESRI Shapefile.
The 0th row of the CSV file can even contain column names, which will then be added to the newly created MySQL table in the database if you like so!
Yet another helpful thing I found out is that while MySQL doesn't support Materialized Views, there is an solution available for a kind of Materialized View which will also give huge performance gains compared to a regular view (as the data is static in the mat.view). The creation of the 'Materialized View for MySQL' here will take some time, just like updating, but querying it is blazingly fast:
DROP TABLE IF EXISTS `myDatabase`.`myMaterializedView`; CREATE TABLE `myDatabase`.`myMaterializedView` SELECT * from `myDatabase`.`myRegularView`;
When I managed to join the 2 tables needed in a view, and then in a Materialized View, I found out that the Materialized View contained all information I needed for my project. So, to speed up the performance, I decided to port it to a NoSQL-database (MongoDb in my case). MySQL makes this pretty easy when you have a table you want to export (and our Materialized View is pretty much a table!), so we can choose to export the data to CSV (or even JSON, which I need to try myself yet!):
If your database is simple and you only have individual tables that you want to import (meaning: there are no JOINs between the tables) you can very simply export your data form MySQL to a CSV file and then import that CSV file with mongoimport to MongoDB.
If we do however have relations, I have found an excellent blogpost here on how to proceed.
I have worked with MongoDb in the past, so I know most of it and it's terms already. However, new users might be confused. That's why I'm also linking an SQL to MongoDB Mapping Chart here for your convenience.