Sqlite on Lloyd Rochester's Geek Blog

SQLite Transactions Part 1

Tue, 09 Jul 2019 06:43:41 +0000

In the world of software these days it is expected that applications do multiple things at once. With that said it’s pretty typical that multiple processes or threads have read and write access to a database. In this post we will go over transactions in SQLite which prohibits changes made to the database unless they are inside a transaction.

Defining a Database Transaction

Let’s first define a database transaction which is essentially to carry out or conduct to a conclusion. In the context of a database a transaction is a grouping of SQL commands. We can consider this transaction to be atomic in the sense that all the commands will execute successfully or it will fail.

Adding SQLite to a C Project

Sat, 06 Jul 2019 10:43:41 +0000

Adding SQLite to a C Project

Let’s add SQLite to your C project. It’s easy and straightforward. We’ll use the SQLite.org recommended way by adding the so-called “amalgamation” to our C project and compile from source. In the words of SQLite.org “the use of the amalgamation is recommended for all applications.” In this blog post we’ll download, compile and use SQLite in our C project.

Step 1 - Download the SQLite Amalgamation

In Step 1 we’ll download the amalgamation and look at the contents of the files. This is done by doing to the SQLite downloads and downloading the zip file in the “C Source Code as an amalgamation” section. Let’s download the zip file and see what is inside it:

Simple SQLite C API Example

Sat, 02 Feb 2019 16:45:00 +0000

When getting started on the SQLite C API they recommend 2 basic ways: sqlite3_exec() and sqlite3_get_table() both are convenience wrappers around the core API Calls. They give good examples for the sqlite3_exec() call, and the sqlite3_get_table() is deprecated in the documentation. Using sqlite3_exec() employs a callback function which gives the advantage of speed and low memory usage - due to being able to process each row at a time. It however, does not allow for knowing when all the rows are returned, as well as, being synchronous.