Category Archives: Oracle Database

An Oracle database is a collection of data treated as a unit. The purpose of a database is to store and retrieve related information. A database server is the key to solving the problems of information management.Many companies has implemented their data in Oracle. Most of them are mission critical. So Oracle database concept need to be very clear to manage these mission critical things. At the same time Oracle database needs to deliver high performance also. A database server also prevents unauthorized access and provides efficient solutions for failure recovery.

Below section I have tried to present all the important features in Oracle Database management

Oracle Recovery Manager :RMAN cheatsheet

Oracle Recovery Manager(RMAN) is an important component of Oracle Database Software . It is a effective way to do the backup and recovery of the Oracle database. Oracle has added new features in RMAN in every new release. Here are some of the article,I have written on RMAN to understand it RMAN benefits over manual backup How to recover database using RMAN How to debug Oracle … Continue reading Oracle Recovery Manager :RMAN cheatsheet »

Oracle Create table Syntax,Tip and Examples

This article talks how to create table in Oracle,create table syntax in oracle,oracle create table example, Oracle is the most RDBMS used everywhere for system Table of content What is Oracle database Table How to create table in oracle create table syntax in oracle Privilege required to create table Other characteristics associated with table How to modify the oracle database table Creation of table using sub … Continue reading Oracle Create table Syntax,Tip and Examples »

Latches and Mutex

INTRODUCTION To LATCH Latches are low level serialization mechanisms used to protect shared data structures in the SGA. The implementation of latches is operating system dependent, particularly in regard to whether a process will wait for a latch and for how long. A latch is a type of a lock that can be very quickly acquired and freed. Latches are typically used to prevent more … Continue reading Latches and Mutex »

Cluster command in Oracle clusterware 10g , 11g and 12c

Oracle clusterware is the clusterware technology from oracle to Manage Oracle RAC database on various platform.Oracle  has provide cluster utilities to manage it. Here are some of the useful Cluster command  in 10g ,11g and 12c  CRSCTL Cluster Control utility performs various administrative operation of oracle clusterware. It is located in $ORA_CRS_HOME/bin and must be executed by the “root” user. Starting and stopping Oracle Clusterware … Continue reading Cluster command in Oracle clusterware 10g , 11g and 12c »

How to delete duplicate rows from Oracle table

Last updated on December 22nd, 2017 at 06:14 pmWe often need to find  and delete duplicate rows from oracle table due to many reasons in the database. We need to delete to clear off the data issues often. There are many ways to oracle delete duplicate rows but keep original .I would be showing off few  faster method to achieve it in this post. Please note … Continue reading How to delete duplicate rows from Oracle table »

Flashback PDB in Oracle Database 12c Release 2

Oracle database 12c Release 2 provides flashback capability at the individual PDB level. Lets discuss the new feature. we can learn about Flashback database in general from below links Flashback Database explained and limitation For the oracle database to be flashback, archive log mode and flashback mode should be on How to put database in archive log mode sqlplus “/ as sysdba” SHUTDOWN IMMEDIATE STARTUP … Continue reading Flashback PDB in Oracle Database 12c Release 2 »

PDB Relocate in Oracle database 12c Release 2

Last updated on December 17th, 2017 at 05:25 pmA pluggable database is a self-contained, fully-functional Oracle database. We often need to move the pluggable database from one CDB to another CDB. This will be a unplug/plug operation where outage will depend on the location of source and destination CDB 1) When moving between servers with shared storage, such as is typically the case in Cloud … Continue reading PDB Relocate in Oracle database 12c Release 2 »

REGEXP string Manipulation

String manipulation and searching contribute to a large percentage of the logic within a Webbased application. Regular expressions are a method of describing both simple and complex patterns for searching and manipulating. Usage ranges from the simple (“Find the word SAN in the text”) to the more complex (“Extract all URLs from the text”) to the archaic (“Find all words in which every second character … Continue reading REGEXP string Manipulation »

How to use Optimizer hints

What is Optimizer? When a query is submitted in Oracle server. optimizer attempts to generate the best execution plan for a SQL statement. The best execution plan is defined as the plan with the lowest cost among all considered candidate plans. The cost computation accounts for factors of query execution such as I/O, CPU, and communication. The best method of execution depends on myriad conditions … Continue reading How to use Optimizer hints »

Refreshable PDB in Oracle Database 12.2

Refreshable PDB is a new features introduced in 12.2 . It builds upon hot clone capability in Oracle Database 12.2. It basically means we can refresh the remote PDB from source PDB on regular intervals by just applying the incremental redo This feature eliminates the need to re-create a cloned environment from scratch and also ensures that a cloned PDB can be periodically synchronized with … Continue reading Refreshable PDB in Oracle Database 12.2 »

ASM best practice to add disk

Here are ASM best practice to add disk which should be always use to manipulate the ASM disks 0) First check the newly added disk is visible in ASM  disksselect header_status,path from v$asm_disk where path= ”; It should show candidate .1) Create a new temporary diskgroup: CREATE DISKGROUP TEST_DISK EXTERNAL REDUNDANCY DISK ”; 2) Check if the diskgroup is created and mounted: SELECT STATE, NAME FROM … Continue reading ASM best practice to add disk »

How to remotely clone a PDB or non-CDB in Oracle Database 12.1

Many times, we may need to copy the remote PDB to Local PDB for testing purpose. The case would be copying Production PDB to Development PDB box. Some times , we may want to migrate the non-CDB to PDB to make sure Multitenant features in the Oracle database Restriction for doing this 1)The default tablespaces for each common user in the remote PDB must exist … Continue reading How to remotely clone a PDB or non-CDB in Oracle Database 12.1 »