Ed Chen Logic - Page 2 of 88 - To Make My Logic More Logical

How to Resolve ORA-01440: column to be modified must be empty to decrease precision or scale

by Ed Chen
March 13, 2021April 11, 2021

ORA-01440 ORA-01440 means that you can't decrease the number precision of the column values directly by modifying the definition of the column. Let's see a… Read More »

How to Add Services to PDB

by Ed Chen
March 6, 2021March 21, 2021

By default, Container Database (CDB) provides only one service for every Pluggable Database (PDB) for connections, but we can create our own services for various… Read More »

How to Resolve RMAN-03009: failure of allocate command on channel

by Ed Chen
March 3, 2021March 14, 2021

RMAN-03009 I used to allocate multiple RMAN channels to backup the database parallelly, but I failed with RMAN-03009 about channel allocation problem. RMAN> run {… Read More »

How to Resolve ORA-01624: log needed for crash recovery of instance

by Ed Chen
February 27, 2021January 28, 2021

ORA-01624 ORA-01624 means that the redo log group that you want to operate with is needed for recovery once the database startup after a crash.… Read More »

How to Modify VARCHAR2 to CLOB of a Column

by Ed Chen
February 24, 2021March 14, 2021

Major Data Types There're several major data types built in Oracle. Character Numeric Datetime LONG RAW LOB (Large Object) In each major data types, minor… Read More »

How RMAN Duplex Backup Copies

by Ed Chen
February 20, 2021January 7, 2021

After knowing how to change the backup location in different scenarios, let's see a more advance topic about making backup copies in RMAN. By default,… Read More »

How RMAN Set Backup Location

by Ed Chen
February 17, 2021March 10, 2021

By default, all backup pieces of RMAN go to Fast Recovery Area (FRA), but we can change it. In RMAN, we can set different backup… Read More »

How RMAN Backup Parallelly

by Ed Chen
February 15, 2021March 10, 2021

To backup the database with multithreads can considerably speed up the backup process as long as IO throughput is good enough to handle high volume… Read More »

How to Remove MGMT Database

by Ed Chen
February 13, 2021March 21, 2021

Some DBA may consider to remove MGMT database because of resource consuming. I myself found that MGMT database is error-prone when we apply patches on… Read More »

How to Relocate MGMT Database

by Ed Chen
February 13, 2021March 14, 2021

The Management Database (MGMTDB), or say Grid Infrastructure Management Repository (GIMR) is a database which collects real time performance data of each node. It can… Read More »