In this article we will explore about uses , features , causes of corruption , errors and steps to repair SQLite Database.

What is SQLite Database

SQLite is an in-process library that implements an autonomous, zero-configuration, transferable SQL Database Engine. Due to its small size its applicable area extends from Windows OS to embedded OS such as ios , android , blackberry , web OS etc. It uses a compelling SQL syntax and performs multitasking for performing read and write operations to ordinary disk files at the same time. SQLite is stored as single cross platform files on host machines. The design is executed by locking the entire database file during the write operation. An SQLite library is invoked dynamically through uncomplicated functions calls , reducing the latency that occurs during accessing the database.

Repair SQLite Database

Due to the mishandling of the files that are stored on the SQLite Database server, corruption issue arises. So it becomes mandatory to implement some repair techniques in order to recover SQLite database.

Distinctive Features of SQLite Database

• No need to install SQLite before it is used. There is no setup procedure that needs to be followed in order to use SQLite database.
• SQLite database does not need any separate server process in order to be implemented. It reads and writes directly from the database files on the disk. This makes it easier for the user to repair SQLite database in case of any database corruption.
• SQLite database is a single disk file that can be located anywhere in the directory hierarchy. In case when the user faces the issue of not being able to open the database file , he can easily access the single disk file and modify it to repair SQLite database from its corrupted state.
• SQLite reduces the load on the network and the central database server , thus it is used in many applications as a cache of relevant content extracted from an enterprise RDBMS.
• The source code of the SQLite is designed in a way that it can be easily worked upon by an average programmer. Sometimes the user faces the memory problems with the SQLite database , so he can easily repair SQLite database all by himself just by making some changes in the statements used to create the tables.

Uses of SQLite Database

• Embedded Devices : SQLite DB requires no administration so it works smoothly on devices that does not require any human support. It is best suited for use in modern devices like smartphones , remote sensors , drones , thermostats , medical devices and robots.
• Application File Format: It is mostly preferred as the on disk format for desktop applications such as version control systems , financial analysis tools , CAD packages and more.
• Data Analysis : Due to its easy installation and small size , SQLite is prefered over enterprise client / server database when analyzing the large sers of data. Raw data is easily imported using CSV files and can be broken down to generate a set of summary reports.
• Cache For the Enterprise Datasets: SQLite reduces the load on the network and the central database server , thus it is used in many applications as a cache of relevant content extracted from an enterprise RDBMS.
• Server Side Database : SQLite is often faster than a client/server SQL database engine as database requests are serialized by the server so the issue of concurrency does not show up.

When To Repair SQLite Database?

SQLite Database shows defiant nature towards corruption. If during the execution of any transaction , if you face any egregious prospect then it depicts that your SQLite database has most probably entered into an inaccessible state. If the transaction process fails , then the actions automatically rolls back and you need to start everything from scratch after being connected to the SQLite Server. There are different reasons which makes the SQLite database inaccessible and the user needs to search for a solution to repair SQLite database. Some of the prominent reasons that lead to loss of access to the database are:

• Overwriting the Existing Files : SQLite being ordinary disk files are much prone to overwriting and there is no way available to defend the database from such actions :
  • Closing and Reinstatiating File Decryptor : It causes overwriting of the threads that are managed in the SQLite Database log files which replaces the data that needs to be on the server which leads to corruption of the database.
  • Transaction ID Mismatch : During the transaction the processes running at the backend of system attempt to create a backup of the SQLite files which includes the log files of the previous state and the earlier transactions due to which there is a mismatch in the transaction ID's leading to a corruption issue.
• Issues in Locking the File : SQLite make use of locking the databases for coordinating the concurrent processes and avoid the changes done by the two processes for a single database.
  • Bugs in Locking Primitives : SQLite is operated on a file system where the locking primitives contain bugs this may lead to corruption of the database.
  • Multiple Threads Accessed Simultaneously : Database is accessed by multiple threads at the same time.
  • Database Replicas linked to same Application : If there are replicas of the SQLite database linking to the same application , then multiple connections to the database will be created and a close() operation on one connection may unknowingly clear the locks on a different database connection that may corrupt the database.
  • Renaming or Unlink action on Database in Use : Unlinking or renaming a DB file while it is being used also leads to a perpetual behaviour of the database.
• Disk Drive Failures : The failure of a disk drive rarely occurs but it can lead to corruption of the database if the contents of the files change due to a disk drive failure.
  • Using Hard Drive to Write Data of Database : Writing the content of the DB from one file format to other while using a hard drive that is not power protected can also cause interruption in the SQLite databases.
  • No Storage : When there is no storage left on the disk and you attempt to write data into it , this can also lead to the corruption of the database.

SQLite Database Errors

• SQLite Error Code 21 : In this case an out of memory error is reported to the user , it means that there is not enough of RAM available that is required by SQLite database to operate.
• SQLite Error Code 14 : This error is returned as SQLITE_CANTOPEN i.e. The database file cannot be opened. It is due to loss of access to the primary database file or one of the temporary disk files.
• SQLite Error Code 11 : When the SQLite Error 11 comes up , the user receives the following message :

  

How to Repair SQLite Database?

SQLite Corrupt Database Recovery Solutions to Restore back to normal state.

• Solution For Error Code 21 :To repair the SQLite database issue , the user needs to add the DATAVALID column in the table which can be done by updating the CREATE TABLE statement.
• Fix Error Code 14 : Change the settings in the directory where the database has been stored , so as to provide write access to the database file. Recover SQLite Database by running the following commands on your web server that runs as www-data :

  

• Solution to Recover SQLite database Error Code 11 : User needs to reinstall the SQLite application. Removing the old database from the system and reinstalling it helps to fix corrupt sqlite database. Solution Repair SQLite database disk image is malformed error so that user can login into the database server.

Conclusion

For different users using the SQLite db on different platforms , they may the mentioned errors in different ways , so there can be different solutions to these errors. The above mentioned errors are a general implementation to solve the errors.