What is PDB and CDB in oracle 12c

Thursday, 10 October 2019

What is PDB and CDB in oracle 12c

Hi DBA-Mates, Hope you all are doing well.

What is PDB and CDB in oracle 12c

Day before yesterday, I give a presentation for my team about 12c features about what is PDB (Pluggable database) and CDB (Container Database).

And the good thing is, I got a good feedback also. So, I thought to share here with you all, it may helpful and tried to explain simple way.

Suppose, we are installing a database 12c, it will contain "Oracle metadata" and after that we put "User data and metadata"

Oracle Metadata (ex. sys and system schema) -- called CDB (Container Database)

User data/metadata -- called PDB (Pluggable database)

Old 11g:

Suppose, we have 2 clients then we have to create/install 2 database on the same server for their access where needed 2 instances, 2 cpus and other background process which makes more loads.

Now 12c Features:

In cloud or SaaS or pluggable Database:

Suppose, we have 1 server and we installed Fresh Database (DB with only Oracle Metadata e.x: like sys and system with objects).

So it will be act like CDB (Container database) or called as CDB (Container DB).

So, there will only one instance and their background process.

Then, there will space provided to users/clients to create their own schema/database.

So, if a client came and asked for database on server, then oracle provider can tell them CDB name, under which they can create their own schema/database.

Same if another user/client came, they can create their own in same server under same CDB.

So, there is no need to install again and again Oracle Metadata/ fresh database, no need to create many instances.

So, also it will be called as SaaS (Software as a Service).

And the User’s metadata or schema’s called as PDB (Pluggable Database)

Note: Of course, for this good hardware and servers required which is available now a days easily, no doubt.

Example in easy language which I have understood it:

Suppose, there is a building with 4 floors, only with hall on every floor. And there are facilities like lift, watchman, water-tanks, garden, bank ATMs.

One person came and he asked the owner that he want only half space in 1^st floor and another person came and asked owner for another half space on 1^st floor.

Owner provided them half-half space. And they (Customers) build the houses as per their requirements.

So, here facilities like lift, watchman, water-tanks, garden, bank ATMs both customers are using same but they have diff-diff ownership's.

Same-way, here land-plot and Facilities are like CDB and customer’s houses are PDB.

Hope this may useful. Thank you all!!!

Some more useful links:

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