first name:
object / relation map
Object-relational mapping
definition:
Through metadata (database mapping between the object and the description) the relationship between the data object is automatically converted to
Usually as middleware
Advantages and disadvantages:
The advantage is automation, shielding the SQL statement, but also can make some automatic optimization
The disadvantage is that much extra overhead (do not ORM would not converted yet?)
background:
As the software complexity of object-oriented programming to enhance mainstream programming
Data persistence generally placed in a relational database. (Could it be that non-relational just for performance?)
Business entity embodied in memory for the object, as reflected in the relational data in the database.
However, this does not translate directly into two, a combination of inheritance objects can not be directly reflected in the database. (what does it mean?)
principle:
And associated object attribute database table field profile by
Field query time to put out the object property to put
insert / update time to put property is bound to the SQL statement, and then automatically execute SQL statements.