Small Basic - Database Extension

Over the years a few people have written simple databases in Small Basic saving data in a text file, then performing sorts or other operations on Small Basic arrays of data.

There were a few recent questions on databases and sorting arrays as well as a challenge question on the Small Basic forum.

• Help with the File.GetFiles command
• LDDatabase extension - SQLite & Using variables to insert values into tables

Here is an example, import ZTC919-1, by Jibba Jabba contributed for this month's challenges (some auto commented File commands need to be un-commented after importing).

And another demonstrating sorts and searches, import CDC823.

This is a great way to learn, but in the real world people usually use commercial databases, which are controlled by a special language, usually SQL (Structured Query Language). 

SQL statements then perform either COMMANDS to modify a database or QUERIES to do searches in the database, returning results.

Learning how to use SQL is a great skill to learn if you are interested in using databases in your programs.  SQL is used by creating a text variable that is passed to the database to perform a COMMAND or QUERY, so most of the work is learning how to create these text commands to do what you want.

In the LitDev extension I created a simple interface to SQLite.  SQLite is a small implementation of an SQL database, where the database is stored in a single file with no special installation or other pre-requisites.  The LitDev extension object for using SQLite is called LDDataBase and has only 4 methods making it quite simple to use.

LDDataBase
SQLite Database with ListView control (see http://zetcode.com/db/sqlite/ for SQLite commands).

AddDataBase(fileName)
Create or open a database.
This must be called before any SQL methods.
When a table is created it must have first column as "Id INTEGER PRIMARY KEY".
fileNameThe full path to the database file (usually with extension db).
returnsA label to identify the database.

AddListView(width,height)
Add a ListView to view database.
widthThe width of the ListView.
heightThe height of the ListView.
returnsThe ListView control.

Command(database,command)
Perform an SQLite command (not a query) on a database.
databaseThe existing database label (see AddDataBase).
commandThe SQLite Command.
returnsThe number of rows updated.

Query(database,query,listview,getRecords)
Perform an SQLite Query (not a command) on a database.
databaseThe existing database label (see AddDataBase).
queryThe SQLite Query.
Example "SELECT * FROM myTable;".
listviewA ListView to populate with the query result or "" for none.
getRecordsOptionally return an array of results ("True" or "False").
Remember large multi-dimensional arrays in Small Basic are slow.
returnsOptional array of results or "".

A simple example comes with the LitDev extension, located in folder other-samples/LDDataBase.sb in the zip download and is based on the samples on the SQLite website.  This is an excellent website and is a great place to start using SQL databases; there are many other good SQL resources and tutorials, for example techonthenet.

The following is a exert from this example.

A ListView is a special control used to display QUERY results like below from the sample.

Using the extension is easy, but mastering SQL is a big challenge.  It is however well worth getting some experience with SQL databases if you are interested in practical computing. 

It is not necessary to learn much SQL to use a database to store and manipulate your data efficiently in Small Basic; the sample contains everything for quite advanced use.  The storage, sorting and querying of the data is then much easier and faster compared to using Small Basic arrays, leaving you free to concentrate on the other features of your program logic.