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In Oracle Database, there are two main architectures:
Non-CDB (non-container database) and CDB (container database) with PDBs
(pluggable databases). Here’s a comparison of these architectures and a method
to identify which type of database you are using:
Non-CDB
(Non-Container Database)
- Architecture: Traditional database architecture where the
database instance and data dictionary exist independently.
- Isolation: Each database is isolated and managed
separately.
- Resources: All resources (memory, processes) are dedicated
to that single database.
- Management: Simpler but less flexible for managing
multiple databases.
- Version: Available in older versions of Oracle Database
but deprecated in Oracle 12c and later versions.
CDB (Container
Database) with PDBs (Pluggable Databases)
- Architecture: Introduced in Oracle 12c, the CDB
architecture includes a root container (CDB$ROOT) and one or more pluggable
databases (PDBs).
- Isolation: PDBs are logically isolated but share the
common resources of the CDB.
- Resources: Shared among multiple PDBs, which can lead to
more efficient resource utilization.
- Management: More complex but offers easier management of
multiple databases within a single CDB.
- Flexibility: Supports rapid cloning, provisioning, and
migration of PDBs.
Identifying Your
Oracle Database Type
You can identify whether your Oracle database is a Non-CDB
or a CDB with PDBs by querying certain views in the database. Here's how you
can do it:
# Step 1: Connect to the Database
First, connect to your Oracle database using SQL*Plus or
another database connection tool.
```sql
sqlplus / as sysdba
```
# Step 2: Check the Database Type
Execute the following query to determine if the database is
a Non-CDB or a CDB with PDBs:
```sql
SELECT NAME, CDB FROM
V$DATABASE;
```
- If the `CDB` column returns `YES`, your database is a CDB.
- If the `CDB` column returns `NO`, your database is a Non-CDB.
# Step 3: Additional Checks for CDB
If your database is a CDB, you can further check for the
presence of PDBs:
```sql
SELECT CON_ID, NAME,
OPEN_MODE FROM V$PDBS;
```
This query will list all the PDBs within the CDB, along with
their container IDs (CON_ID) and open modes.
Example Outputs
# Non-CDB Database
```sql
SQL> SELECT NAME,
CDB FROM V$DATABASE;
NAME CDB
--------- ---
ORCL NO
```
# CDB with PDBs
```sql
SQL> SELECT NAME,
CDB FROM V$DATABASE;
NAME CDB
--------- ---
CDB1 YES
SQL> SELECT
CON_ID, NAME, OPEN_MODE FROM V$PDBS;
CON_ID NAME OPEN_MODE
------ --------- ----------
2 PDB$SEED READ ONLY
3 PDB1 READ WRITE
4 PDB2 MOUNTED
```
Summary
- Non-CDB: Single standalone database, simpler architecture,
and dedicated resources.
- CDB/PDB: Container database with one or more pluggable
databases, shared resources, and greater flexibility for managing multiple
databases.
By running the provided queries, you can easily determine
whether your Oracle database is a Non-CDB or a CDB with PDBs.