{ "date": "2015-11-30T17:45:09", "slug": "ocm-12c-preparation-manage-pdb", "link": "https://www.dbi-services.com/blog/ocm-12c-preparation-manage-pdb/", "title": { "rendered": "OCM 12c preparation: Manage PDB" }, "content": { "rendered": "

By Franck Pachot

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\nLet’s see the different ways to create a PDB, with different tools.
\nSame disclaimer here as in the first post of the series: don’t expect to get those posts close to what you will have at the exam, but they cover important points that matches the exam topics.

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Documentation

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Information about the exam says: Be prepared to use the non-searchable documentation during the exam, to help you with correct syntax.
\nDocumentation about the ‘Create and manage pluggable databases’ topic is mostly in the Oracle® Database Administrator’s Guide. Search for ‘multitenant’, expand ‘Creating and Removing PDBs with SQL*Plus’

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You find all examples there. Remember that creating a PDB is always done from another one:

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and the you will name your datafiles with a conversion from the original ones.

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Don’t forget to create the directories if you are not in OMF.

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SQL Developer

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SQL Developer is your friend. It is designed to help you. I use it in the following way:

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I’ll show you an example. You have several ways to name the files when you create a pluggable database, using the convert pairs. But if you have more than one pattern to replace, it’s not easy. Let’s use SQL Developer for that.

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In the DBA tab, right click on the Container Database and you have all possible actions on it:

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\"Capture12COCMU-CreatePDB-000\"

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Here are all option for the CREATE PLUGGABLE DATABASE statement. Easier that going to documentation:

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\"Capture12COCMU-CreatePDB-001\"

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Above I’ve chosen ‘Custom Names’ to list all files. Then let’s get the SQL:

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\"Capture12COCMU-CreatePDB-002\"

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Now, I prefer to continue in the SQL Worksheet and I can paste it there. I’ve a file_name_convert pair for each files, so that I can change what I want:

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\"Capture12COCMU-CreatePDB-003\"

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SQL Developer is really a good tool.
\nWhen you unplug a PDB, it is still referenced by the original database. Then is you plug it elsewhere without renaming the files, the risk is that you drop it’s datafiles from the original container database.
\nBest recommendation is to immediately remove it from the original CDB and this is exactly what SQL Developer is doing:

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#12COCMU Good point @OracleSQLDev
A safe unplug must immediately remove the PDB from the original CDB pic.twitter.com/Cdh1k7fpio

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— Franck Pachot (@FranckPachot) November 30, 2015

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dbca

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DBCA is not my preferred tool to create a PDB, but let’s try it.

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Let’s start by some troubleshooting (which is not what you want to do at an exam):
\n\"Capture12COCMU-CreatePDB-005\"

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Well it is open. Let’s troubleshoot. dbca log is in $ORACLE_BASE/cfgtoollogs/dbca and I found the following:

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\n[pool-1-thread-1] [ 2015-11-29 19:22:42.910 CET ] [PluggableDatabaseUtils.isDatabaseOpen:303]  Query to check if DB is open= select count(*) from v$database where upper(db_unique_name)=upper('CDB') and upper(open_mode)='READ WRITE'\n...\n[pool-1-thread-1] [ 2015-11-29 19:22:43.034 CET ] [PluggableDatabaseUtils.isDatabaseOpen:334]  DB is not open\n
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Actually, I’ve no DB_UNIQUE_NAME in v$database:

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\nSQL> select db_unique_name from v$database;\n\nDB_UNIQUE_NAME\n------------------------------\n\n
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I’ve the db_unique_name for the instance:

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\nSQL> show parameter uniq\n \nNAME                                 TYPE        VALUE\n------------------------------------ ----------- ------------------------------\ndb_unique_name                       string      CDB\n
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but it’s the default (equals the db_name) as I didn’t set it in the init.ora when I created the CDB manually.
\nLet’s try to set it:

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\nSQL> alter system set db_unique_name='CDB' scope=spfile;\nalter system set db_unique_name='CDB' scope=spfile\n*\nERROR at line 1:\nORA-32001: write to SPFILE requested but no SPFILE is in use\n
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Ok, now I understand. I’ve created the spfile but didn’t restart the instance since then.

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\nSQL> startup force\nORACLE instance started.\n\nTotal System Global Area 1073741824 bytes\nFixed Size                  2932632 bytes\nVariable Size             335544424 bytes\nDatabase Buffers          729808896 bytes\nRedo Buffers                5455872 bytes\nDatabase mounted.\nshow parameter Database opened.\nSQL> show spparameter unique\nSQL> select db_unique_name from v$database;\n\nDB_UNIQUE_NAME\n------------------------------\nCDB\n \n
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Here it is. It’s not set in spfile, but takes the default. When we start with a pfile where it’s not set, it is not there in V$DATABASE.

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My conclusion for the moment is: if you didn’t create the database with DBCA there is no reason to try to use it later.

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And the most important when you create a PDB is written in the doc:

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#12COCMU backup the PDB after creation (suppose CDB has a backup already) pic.twitter.com/p8I08p3boO

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— Franck Pachot (@FranckPachot) November 29, 2015

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