ORM in computer software stands for Object Relational Mapping, which is a technique for mapping system types into Relational Database types and make DB tables available for use as Objects and Classes, thus creating virtual Object-Relational Database.
In ORM, a one Class instance is mapped to one Relational Database table record. for example, suppose we have a table called “users” that have three columns “id”, “full_name” and “email_address”, to express this table into Object a Class that have three member variables that is mapped to the three table’s columns, converting columns values from Database data types into system types when querying for records and back into columns data types when saving or updating record.
Every software technique has come to solve an issue, reduce cost, time and effort. ORM – alike – is here for the sake of making Developers’ life easier when it comes to dealing with Databases.
Many ORM softwares – both commercial and open source – are off the shelf to pick and use, and as always, each software has its own hassle, for instance looking at libraries implemented using Java language you can find many ranging from complex to plain ORM implementations.
obstacles raise when it comes to implementing ORM softwares, this can be viewed from database and software side; as for database side: we can talk about securing data integrity, doing Joins and bulk operations. and from software point of view we can talk about performance, debugging and concurrency.
