SQLite is an embedded database management system. It is very lightweight database model, with no installation required, zero configuration, and no server required.
Despite its simplicity, it is laden with other features of database management systems.
Here is what we cover in the Course
SQLite is a relational database management system. It was designed originally on August 2000. It is an Open source software.
SQLite is very lightweight; it is less than 500Kb size. Unlike other database management systems like SQL Server, or Oracle.
SQLite is not a client-server database management system: it is an in-memory library that you can call it and use it directly, no installation and no configuration required.
A typical SQLite database will be contained on a single file on the computer disk storage with all the database objects (tables, views, triggers, etc.) included on that file, no dedicated server required.
When to use SQLite:
Whenever you need a lightweight database, if you are developing an embedded software for devices like televisions, Mobile phones, cameras, home electronic devices, etc. then SQLite is a good choice.
If you want to manage complex session information for a website, SQLite can handle low to medium traffic HTTP requests.
When you need to store an archive of files, SQLite can produce smaller size archives and much amount metadata included than regular ZIP archives.
If you want to do some processing on some data within an application, you can use SQLite as a temporary dataset. You can load the data into an SQLite in-memory database and do the queries the way you want. You can extract the data in the way you want back to your application.
It gives you an easy and efficient way to deal with data rather than do the data processing internally inside in-memory variables. For example, if you are developing a program and you have some records that you want to do some calculations on them. Then you can create an SQLite database and insert the records there, and with only one query, you can select the records and do the calculations you want on them directly.
When you need a database system for learning and training purposes, SQLite is a good fit for that. As we explained, no installation and no configuration are required. Just copy the SQLite libraries in your computer and is ready for creating the database.
Why to use SQLite:
It is all free – SQLite is an open source, no license required to work with it.
SQLite is cross-platform database management system; it can be used on a broad range of different platforms like Windows, Mac OS, Linux, and Unix. It can also be used on a lot of embedded operating systems like Symbian, and Windows CE.
SQLite offers an efficient way for storing data, the length of the columns is variable and is not fixed. So SQLite will allocate only the space a field needs. For example, if you have a varchar(200) column, and you put a 10 characters' length value on it, then SQLite will allocate only 20 characters' space for that value not the whole 200 space.
A broad range of SQLite APIs – SQLite provides APIs for a broad range of programming language, for example.Net languages (Visual Basic, C#), PHP, Java, Objective C, Python and a lot of other programming language.
- SQLite is very flexible.
- SQLite variables are dynamic typed, meaning that the type of the variable is not determined until it is assigned a value, and not on the declaration.
- INSERT ON CONFLICT REPLACE statement. With this statement, you can tell SQLite to try to do an insert on a table and if it found rows with the same primary keys, then update them with the values from the inserted values.
- With SQLite, you can work on multiple databases on the same session on the same time. just attach those databases and then you can access all the databases' objects (tables, views, etc..) on the same time.
The following are the list of unsupported features and limitations in SQLite:
SQLite doesn't support neither RIGHT OUTER JOIN nor FULL OUTER JOIN. It supports only LEFT OUTER JOIN.
- Limitations in ALTER table statement: with ALTER TABLE statement in SQLite you can only add a column or rename a table (as we will see in the following tutorials). However, you can't do the following:
- ALTER column.
- DROP a column.
- ADD a constraint.
VIEWs are read-only – you can't write INSERT, DELETE, or UPDATE statements into the view. However, you can create a trigger on a view and do the INSERT, DELETE, or UPDATE statements into it.
GRANT and REVOKE commands are not implemented in SQLite. There are only normal file access permissions implemented in SQLite. This is because SQLite reads and writes to the disk files, unlike other Database management systems.
TRIGGERS – As we will see in the incoming tutorials, SQLite only supports FOR EACH ROW triggers, and it doesn't support FOR EACH STATEMENT triggers.