Triggers are generally used to enforce business regulations, auditing changes in the database and replicating information as well. A very well known trigger is Data Manipulation Language (DML) that activate when data is interrupted. A number of database systems support non data triggers, which are caused when Data Definition Language (DDL) events happen. A few examples are triggers that are established when views are made, during rollback operations or commit. They are also used for auditing purposes. Moreover, Oracle database system validates schema level triggers. These triggers are made when database schemas are updated like After Creation, After Alter, Before Alter, After Drop, Before Drop among others. The four main kinds of triggers supported by Oracle are Row Level triggers, Each Row Type triggers, For Each Statement Type triggers and Column Level triggers.
Understand that if data processing operation needs a number of SQL statements to be executed, these are implemented as stored procedures. Use a CALL or EXECUTE statement when citing a stored procedure. They are supposed to return results. For instance, results from the SELECT statements which can be later used by applications or other stored procedures. Languages that write them usually support control structures like if, for, while, etc. A variety of languages can be used to implement stored procedures such as PL, SQL, Java in Oracle, T-SQL and .NET Framework in Microsoft SQL Server.