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June 18th 2014, SQLite

← June 15th 2014 Transmission Meta Data | ● | June 18th 2014 QSqlDatabase →

Transmissions that arrive on the server must be stowed away. Later on they may be removed or transferred to another destination, but first the transmissions need to be kept in a safe way. A convenient way to do this is SQLite.

A SQLite database is mapped to a single file, which contains data stored in a key/value schema. To store a bunch of files in a SQLite database, we simply use a key/value schema with the key being the file name and the value being a blob with the file contents. In the high-level SQL language description such a schema is created with the following SQL statement: 

CREATE TABLE files(filename TEXT PRIMARY KEY, content BLOB);

If the data is stored in a compressed format (e.g. using qCompress()), then the database is not much larger than the same amount of data stored in a zip file. Nevertheless, it is much easier to access the stored data because:

  • The database can be queried with the SQL high-level languange.
  • Any amount of data tables or relations can be stored in the db as well.
  • Transactions on the database are safe, meaning that a power failure cannot corrupt the data.
  • Transactions are thread-safe, also.
  • Since that data is contained in a single file, it is easy to back up.
  • The database format is platform independent
  • File names do not need to adhere to any platform specific conventions, since they are just a key text string in the database table.
  • No need to waste time thinking about efficient storage of the data, the SQLite database developers have already arranged everything for us.
  • SQLite is stable and tested.
  • SQLite is a server-less database. It is a so-called application embedded database, so there is no concept of users and passwords, but there is also zero configuration overhead.
  • External access to the database is possible through widely available maintenance and statistics tools.
  • The entire source code of SQLite is in the public domain, so it is completely free to use.


← June 15th 2014 Transmission Meta Data | ● | June 18th 2014 QSqlDatabase →

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