How to Fix Sqlite Error Code 21 ? – SQLITE_MISUSE

admin | July 14th, 2015 | General

Introduction

Many of the application currently are using Sqlite like; data analysis, websites, embedded devices, airplanes, etc. Sqlite is not a client-server database engine and further, no separate server for Sqlite; hence it is zero configuration databases. A library is linked with the Sqlite, size of 500KiB thus, making it the integral part of application programs. All the transactions are followed with ACID property so, no data loss even when crashed. We can call Sqlite as small, fast and reliable database engine and it reads and writes to disk files directly. Sqlite is an advanced form of SQL query language but, some commands are omitted and the recommended version of Sqlite is 3.8.10.2. While running Sqlite, there is a possibility of getting errors. Here, we have discussed about it.

What are Error Codes?

We all know about what is an error, it is clear from the word; “something is wrong”. There are possibilities of error in Sqlite too. Error codes are the subset of ‘Result Codes’, which is of 32 bit integer. The least significant 8 bits is the primary result code and the MSB provides the detailed information and is called extended result code. So, primary code is a part of extended result code. There are many codes returned by the Sqlite functions which indicate whether it is a failure or success. One such error code is SQLITE_MISUSE i.e. Sqlite Error code 21.

Let us see the error in detail.

Error SQLITE_MISUSE (Sqlite Error Code 21):

Sqlite error code 21 indicates that the “library used is incorrect”. The code is returned as the result of undefined way of using the Sqlite interface by the applications.

The Sqlite detects the misuse, if any; and reports it by specifying the code but, it is not always correct. We can say that, misuse detection is always probabilistic; i.e. not sure whether correct/not.

NOTE: Remember if the SQLITE_MISUSE 21 is never returned then, the application is incorrect and needs to fix up.

How Can We Detect The SQLITE_MISUSE Error Code?

As mentioned above that, misuse detection is probabilistic then we cannot rely on just the code fully. Here are some of the ways by which SQLITE_MISUSE arrives.

The error code can happen because of trying to bind values to a statement that is currently running.
When trying to access the same databases by two or more threads at same instance of time.
While calling API routine with Sqlite3* pointer which is not obtained from Sqlite3_open()/Sqlite3_open16().
While calling Sqlite3_step() with Sqlite3_stmt* pointer which is not obtained from Sqlite3_prepare().

Many codes result in Sqlite informing whether the Sqlite functions are functioning properly or not. Manual correction is time consuming and may create more errors sometimes. So, the error codes found can be corrected using a commercial solution like the software – Sqlite Database Recovery. The software helps to recover the corruptions and errors of the database and can be exported to corresponding database as requirement specified.