OODBMS postgreSQL array Fields real Use?

I am new to PostgreSQL, mainly used MySQL before and SQLServer(for Clients Pressure; donno much), I've gone through several OODBMS Introductories over some Google Search. Most of them mainly focuses on Table <-> Object Mapping. But When using some Generic ORM Layer with any RDBMS Things are Hapily Mapped. So do we really need OODBMS ?

I've seen there are some Array fields in PostgreSql. Don't they violet the Database Normalization Issues ?

Do Standard Database Abstraction Layers like PHP's PDO or Qt's Database Module support these array fields ?

How better it is to manage Many-to-Many or one-to-many bidirectional relationships with array based fields ?

How wroth is Placing Constraints in these array Fields ?

What is the use of OIDs and How worth it is ?

From the Application Developer's side How much is the gain of Using a开发者_开发百科n OODBMS vs RDBMS ?

I've seen there are some Array fields in PostgreSql. Don't they violet the Database Normalization Issues ?

Yes (maybe), Normalization is supposed to maintain database integrity and maintain the database in a state to make it easy to query. An array or linked list would make your ASNI/ISO issue database facilities very much useless for querying and performing aggregates and joining and such. I don't know what tools Postgres includes (hence maybe) but they're definitely not standard, and therefore not portable. That said, standards compliance doesn't mean a project is executed "correctly"