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--- multitenantarchitecture [2015/07/28 08:37] – created z0hpvk
+++ multitenantarchitecture [2025/03/08 22:24] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 ===== Multitenant Architecture =====
+==== Advantages ====
+  * Database Consolidation
+  * Reduced Costs
+  * Rapid Implementation
+  * Simplified Management
+  * Separation of Duties
+  * Simplified Tuning
+  * Simplified Patching
+==== Creating a CDB ====
+Create spfile setting parameter ENABLE_PLUGGABLE_DATABASES = TRUE\\
+Create instance by specifying STARTUP NOMOUNT\\
+Create database using CREATE DATABASE command, adding new clause ENABLE_PLUGGABLE_DATABASES. \\
+ If you are not using OMF you must either ... \\
+ Use the SEED FILE_NAME_CONVERT option or set PDB_FILE_NAME_CONVERT in spfile \\
+Connect to root and run scripts to create data dictionary\\
 ==== Opening / Closing Pluggable Databases ====
 <code>SQL> alter session set container = pdb2;
@@ Line 17: / Line 34: @@
 Pluggable database altered.</code>
+I think it always safer to use the "alter pluggable" command so you definitely know which database you are closing.
+Sometimes you may get an error when opening a pluggable database
+<code>SQL> alter pluggable database pdb2 open;
+Warning: PDB altered with errors.</code>
+The "show pdbs" reveals that pluggable database pdb2 has been opened in restricted mode.
+<code>SQL> show pdbs
+    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
+---------- ------------------------------ ---------- ----------
+PDB$SEED			  READ ONLY  NO
+PDB1 			  READ WRITE NO
+PDB2 			  READ WRITE YES</code>
+Use the view PDB_PLUG_IN_VIOLATIONS to see what the error is.\\
+The full error message is not always written to the Alert Log.
+<code>select time, message from pdb_plug_in_violations;
+TIME                      MESSAGE
+------------------------- --------------------------------------------------------------------------------
+-JUL-15 08.59.31.507182 Sync PDB failed with ORA-959 during 'CREATE USER c##ian IDENTIFIED BY *DEFAULT T
+                          ABLESPACE "USERS" TEMPORARY TABLESPACE "TEMP" container = all'</code>
+In the above case I had forgotten to create the tablespace users in database pdb2.
+==== Unplugging a PDB ====
+<code>SQL> alter session set container=pdb2;
+Session altered.
+SQL> shutdown immediate;
+Pluggable Database closed.
+SQL> show pdbs
+    CON_ID CON_NAME			  OPEN MODE  RESTRICTED
+---------- ------------------------------ ---------- ----------
+PDB2 			  MOUNTED
+SQL> conn / as sysdba
+Connected.
+SQL> alter pluggable database pdb2 unplug into '/home/oracle/pdb2.xml';
+Pluggable database altered.
+SQL> select pdb_name, status from dba_pdbs;
+PDB_NAME	STATUS
+--------------- ---------
+PDB$SEED	NORMAL
+PDB1		NORMAL
+PDB2		UNPLUGGED
+SQL> drop pluggable database pdb2;
+Pluggable database dropped.</code>
+==== Plugging In an Unplugged PDB ====
+For this example I will simply plug back in the database that was dropped from above.\\
+If I was moving the PDB to a new location on the server I would need to use the 'copy' parameter at the end of the command.
+<code>SQL> create pluggable database pdb3 using '/home/oracle/pdb2.xml';
+Pluggable database created.</code>
+The database is in MOUNTED mode and must be opened after it has been created.\\
+The Service Name was created automatically when the PDB was plugged in.