a Large one table with 100 column vs a lot of little tables

Question

I created some website which contain users,comments,videos,photos,messages and more.All of the data is in the one table which contain 100 column.I thought one table is better th

Answer 1

Wide tables can cause performance problems if they are wider than the database can store in one place.

You need to read about normalization as this type of structure is very bad and is not what the database is optimized for. In your case you will have many repeated records that you will have to use distinct (which is a performance killer) to get rid of when you want to only show the user name or the comments.

Additionally, you may have some fields that are repeats like comment1, comment2, etc. Those are very hard to query over time and if you need another one, then you have to change the table structure and potentially change the queries. That is a bad way to do business.

Further when you only have one table, it becomes a hot spot in your database and you will have more locking and blocking.

Now also suppose that one of those pieces of information is updated, now you have to make sure to update all the records not just one. This can also be also a performance killer and if you don't do it, then you will have data integrity problems which will make the data in your database essentially useless. Denormalizing is almost always a bad idea and always is a bad idea when done by someone who is not an expert in database design. There are many ramifications of denormalization that you probably haven't thought of. Overall your strategy is sure loser over time and needs to be fixed ASAP because the more records you have in a database, the harder it is to refactor.