SQLite is a popular relational database management system excessively used in these days. But unlike other database management systems, it's not a client-server database engine. In fact, it's embedded into the end program. SQLite is widely supported by various browsers, operating systems, embedded systems and many other applications. If you want an open-source and embedded database program for local/client storage in application software, you must use SQLite.
Just like other database programs, SQLite also creates a database file. Since it's an open-source program, it doesn't use any specific file extension. Sometimes corruption can cause severe issues and put SQLite data at high risk. We all know that database files are highly prone to corruption due to its large size and complicated file structure. Like any other file, the SQLite database file is not immune to corruption. There are various reasons which cause corruption, and you must know them. If you're aware of the most common reasons of corruption, you can take the correct measures to avoid them.
Though file locking problem looks normal, but sometimes they can cause severe damage. SQLite uses file lock system for the database file as well as WAL (Write-Ahead Logging) file. The primary function of the file lock system is to coordinate access between concurrent processes. Sometimes, two threads or processes may cause incompatible changes to a database file without proper coordination.
SQLite database is actually an ordinary disk file. This means any process can easily open it and overwrite it with junk characters or make unwanted changes. Any bad thread or process can cause such an appropriate action with ease, even SQLite library can't help you in this situation.
If any failure occurs in the disk drive or flash memory, this can corrupt SQLite database. This can cause changes or alteration in the file content, and lead to corruption.
SQLite has many built-in protections which work against database corruption. But sometimes, many of these protections are disabled due to configuration options. This will result in corruption in SQLite database files.
Almost all programs contain some internal bugs. The SQLite database program has some minor bugs which may cause corruption.
Corruption makes SQLite database inaccessible. In such situation, you have three options:
Valid backup for the database
Manual trick to repair SQLite database
Professional SQLite database recovery solution
If you're having a valid backup, you can easily restore SQLite database from it. But if you don't have any backup, you should try to repair SQLite database manually. If you're using SQLite database browser, you just need to follow these simple steps:
Step 1: Launch DB Browse for SQLite on your system. Click Execute SQL tab in order to run database check command.
Step 2: Type this command - PRAGMA integrity_check, and click the play button.
Note: Since the database is corrupt, you would see an error message(s).
Step 3: So now you should try to export the database into SQL file. Click File tab on top > Export > Database to SQL file.
Step 4: On Export SQL dialog box, select the objects you want to export. You can define other options as well.
Step 5: You can start the process by clicking OK. Please wait until the process is completed.
Step 6: After that, you can import the database back to SQLite browser. Click File tab on top > Import > Database from SQL file.
You can now check your database. It's fine now. Or if corruption is still there, you should use a professional recovery solution. There are many software vendors in the market which provide such recovery solutions with free demo/trial version. Generally, demo/trial version is used for the free evaluation purpose. If you use demo/trial version, you can see what you could recover from the corrupt database file before you can actually pay for the software.