Continuing my last post. When using SQL database a very important aspect is the table schema. What is the best schema for a table. I feel we can never say this definitely we can only try making it better. We had 2 choice when deciding on the schema for the notification app. One notification table for all types of notification (Owner, Group and Watching) Three notification table for 3 types of notification We decided to go with the second option. You ask why. The needs of the three notification are totally different. For example, owner notification needs to be related to User table while Group notification needs to be related to the group table. If we had used option 1 we would have many columns with null values for a large set of rows (remember this is SQL not NoSQL) creating a table with sparse data. Owner notification table schema is as follows: Column Name Data Type Data Range Description message String Notification messag...