In common law, past legal precedents or judicial rulings are used to decide cases at hand. Under civil law, codified statutes and ordinances rule the land.
In more common language what is commonly practiced (past precedence) and what is written in the constitution of the country both are law where as in civil law system only later one is applicable.
Since scrutinize of past precedence takes a lot of time so common law system is slower then civil law but it is very useful in cases where constitution is silent.
