Introduction
Providing local data storage in an application is a real problem faced by many a C++ programmer. To avoid getting oneself confused with low-level file handling routines and chores like data indexing, most programmers tend to use commercial database systems even for minimum data handling purposes. If your application doesn't need the capabilities of a complete RDBMS server, then a small and efficient database library that plugs into your source code will seem an interesting solution. DarkSide SQL Mini is an effort to create such a library. You can take this as a beta release and I want developers to test this code and report bugs before the stable release. You may find even this beta release useful in many of your projects. The best thing about DarkSide SQL Mini is that, unlike other embedded database libraries, you don't have to learn a new set of APIs. It provides a subset of SQL that you can use to define schemas and manipulate data. All you have to learn to use are two classes (Database and ResultSet) and two member functions (execute() and executeQuery())!. Everything else is plain SQL.
Using the code
DarkSide SQL Mini is a source code library. Copy all CPP files in the \dsqlm_1\cpp folder to your projects working directory, add the \dsqlm_1\include directory to your include path, link your object code with dsqlm_1\libdb41s.lib and you are done. You have a nice database system embedded in your application. Now on to some SQL lessons...
First include dsqlm.h in your CPP file:
#include "dsqlm.h"
using namespace dsqlm;
Next create a database object:
Database db("zoo");
This will create the folder zoo, if it does not exist. To create a table, call the CREATE TABLE command.
db.execute("CREATE TABLE animals(name varchar(40) indexed,age int,dob date)");
Data is inserted using the INSERT command:
db.execute("INSERT INTO animals VALUES('Joe',2,'2001-2-20')");
SELECT command is used to search and retrieve data:
ResultSet rslt = db.executeQuery("SELECT * FROM animals WHERE age > 1");
while(rslt.next()) {
cout << rslt.getString(1) << rslt.getString(3) << endl;
}
The above code will print the name and date of birth of all animals whose age is above 1. In addition to these commands, DarkSide SQL Mini supports DELETE, DROP TABLE, DROP DATABASE and OPTIMIZE commands. The installation contains detailed documentation on the library.
In the demo code, you will find a complete working program that demonstrates the use of various DarkSide SQL commands. Follow the instructions in DarkSide SQL Mini Help files to compile this code.
If you need a complete RDBMS server, you can download DarkSide SQL server for free.
History
- Created: Nov 23rd, 2003
- Updated: Nov 27th, 2003: Fixed bug in logical expression parsing.
