How to Switch from CDB to PDB
In the world of database management, the transition from a CDB (Container Database) to a PDB (Pluggable Database) can be a significant step for many organizations. This article aims to provide a comprehensive guide on how to switch from a CDB to a PDB, covering the reasons for making this switch, the prerequisites, and the step-by-step process involved.
Why Switch from CDB to PDB?
The primary reason for switching from a CDB to a PDB is the enhanced flexibility and scalability that PDBs offer. With PDBs, you can create multiple databases within a single CDB, each with its own set of users, schema, and data. This allows for better resource utilization, easier management, and simplified backup and recovery processes. Additionally, PDBs provide improved security, as each PDB can have its own set of privileges and policies.
Prerequisites for Switching to PDB
Before you embark on the journey of switching from a CDB to a PDB, there are several prerequisites you need to meet:
1. Ensure that your Oracle Database version is 12c or higher, as PDBs are only available in these versions.
2. Verify that your CDB is in the correct state to be converted into a PDB. This means it should be open and mounted.
3. Make sure you have enough storage space to accommodate the new PDBs.
4. Have a backup of your CDB, as the conversion process can potentially affect your data.
Step-by-Step Process to Switch from CDB to PDB
1.
Preparation
– Verify that the prerequisites mentioned above are met.
– Take a backup of your CDB to ensure data safety during the conversion process.
2.
Creating a PDB
– Connect to your CDB as the SYSDBA user.
– Use the following command to create a new PDB: `CREATE PLUGGABLE DATABASE newpdb FROM cdb_name INCLUDING USER_DATA;`
3.
Verifying the PDB
– Connect to the new PDB using the following command: `CONNECT / AS SYSDBA`
– Verify that the PDB is operational and that all the necessary objects and data have been successfully transferred.
4.
Shrinking the PDB
– If required, you can shrink the PDB to reduce its size and optimize storage usage. Use the following command: `ALTER PLUGGABLE DATABASE newpdb SHRINK SIZE 100M;`
5.
Testing the PDB
– Perform a thorough testing of the PDB to ensure that all functionalities are working as expected.
6.
Deactivating the CDB
– Once you are confident that the PDB is operational, you can deactivate the CDB by using the following command: `ALTER PLUGGABLE DATABASE cdb_name CLOSE;`
7.
Deleting the CDB
– Finally, you can delete the CDB to free up resources. Use the following command: `DROP PLUGGABLE DATABASE cdb_name INCLUDING DATAFILES;`
Conclusion
Switching from a CDB to a PDB can be a complex process, but following this guide can help you navigate through the transition smoothly. By leveraging the benefits of PDBs, such as improved flexibility, scalability, and security, your organization can achieve better database management and performance.
