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First Steps in SQLite

Foreign key example:

In this tutorial I will show you how to crate a small SQLite DB with 3 tables and assign foreign keys to some parameters in the 3rd table. I’ve used “SQLite Database Browser” tool to crate database and tables inside. You can find this tool @ here. As all you know Android support small SQL database, this SQLite is stripped down version of standard SQL’s db. This fact can crate some problems to users so let’s take a look at the SQLite limitations:

  • Maximum length of a string or BLOB
  • Maximum Number Of Columns
  • Maximum Length Of An SQL Statement
  • Maximum Number Of Tables In A Join
  • Maximum Depth Of An Expression Tree
  • Maximum Number Of Arguments On A Function
  • Maximum Number Of Terms In A Compound SELECT Statement
  • Maximum Length Of A LIKE Or GLOB Pattern
  • Maximum Number Of Host Parameters In A Single SQL Statement
  • Maximum Depth Of Trigger Recursion
  • Maximum Number Of Attached Databases
  • Maximum Number Of Pages In A Database File

You can find more details here and SQLite FAQ.

Let me start creating two tables, but you may use more tables if you want to. In both tables I have defined one parameter as PRIMARY KEY. Pay attention to the SQL parameter NOT NULL, in this case I didn’t add this to the parameter in the table. You will find out later why.

Next, we need to crate a table which has two foreign keys, one that relates reportTB table with eventTB table, and the same for the second foreign key which relates the reportTB table to userTB table:

Add some data

How to test… easy