The biggest feature of SQLite is that the data type is untyped. This means that you can save any type of data in any column of any table you want to save, regardless of the data type declared by that column. Although the data type of each field should be declared when generating the table structure, SQLite does not do any checking. Developers should rely on their own programs to control the types of data input and read. There is an exception here, that is, when the primary key is an integer value, if you want to insert a non-integer value, an exception will appear.

Although SQLite allows you to ignore the data type, it is still recommended to specify the data type in the Create Table statement, because the data type is conducive to enhancing the readability of the program. In addition, although there is no distinction between types when inserting or reading data, different data types are different when comparing.