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

Virtual IP Addresses(VIP) in Oracle RAC

What is VIP in Oracle RAC? High Availability (HA) databases are less than satisfactory if database clients are unable to connect or reconnect quickly when planned or unplanned downtime causes one or more instances to become unavailable. Database clients use TNS descriptors to contact a TNS listener on one of the cluster nodes from a list of listeners on all cluster nodes. TNS descriptors for … Continue reading Virtual IP Addresses(VIP) in Oracle RAC »

What is voting disks in RAC

Last updated on April 1st, 2017 at 08:09 amVoting Disks in RAC Description Voting disk is a file that manages information about node membership.It is located on the shared cluster system or a shared raw device file or ASM(11gr2 onwards) .Its primary purpose is to help in a situation where the private network communication fails.CSS (Cluster Synchronization Service) is the service that determines which nodes … Continue reading What is voting disks in RAC »

Demonstration/Viewlet/Videos for Many Oracle features

Oracle has provided lot  of Demonstration/Viewlet/Videos on Oracle features like RMAN,Flashback,standby etc Each demonstration has a description and links to the demo.  Some demos have a ‘demo’ link that will play in your browser on any platform.  Others have a ‘download’ link which will download an executable file to your computer that will only play on a Windows system. Some demos offer both options. Here … Continue reading Demonstration/Viewlet/Videos for Many Oracle features »

How to resolve ORA-00904: invalid identifier

ORA-00904: invalid identifier is one of the common error seen. Reference: Oracle documentation One of the most common cause of this error Invalid identifier means the column name entered is either missing or invalid. It also Some time comes  when you used reserved word in Oracle database. Check List to resolve the ORA error  It comes when you put extra comma in the create table … Continue reading How to resolve ORA-00904: invalid identifier »

How to work with date in Oracle sql

Last updated on April 1st, 2017 at 10:02 amThis post I am trying to explain many things  about oracle date datatype like oracle sql date functions,oracle sql date format, oracle sql date comparison, oracle date difference in  years,oracle date difference in  days, oracle date difference in  months Oracle has provided date and timestamp type for storing the date and time information in the database. Date Type DATE is … Continue reading How to work with date in Oracle sql »

How to resolve ORA-00900

ORA-00900 is one of the common error Here what oracle documentation says about it Reference: Oracle documentation Checklist to solve the ORA-00900 error This error commonly occurs when you are trying to create an Oracle procedure and the Procedural Option is not installed.To determine if the Procedural Option has been installed, open an Oracle session using SQL*Plus. If the PL/SQL banner does not display, then … Continue reading How to resolve ORA-00900 »

How to resolve the ORA-01017: invalid username/password; logon denied

ORA-01017  is one of the common error seen in PLSQL programs. Here is what documentation says about this error Here are the checklist to run to resolve the error The main issue with an ORA-01017 error is an invalid user ID and passwords combination.  You have to make sure ,you are entering the right password Incase the target system is 11g, the password can be … Continue reading How to resolve the ORA-01017: invalid username/password; logon denied »

How to resolve ORA-06512 at line num

ORA-06512  is one of the common error seen in PLSQL programs. Here is what documentation says about this error Reference :Oracle documentation Explanation of the error: Error Ora-06512 means the backtrace message as the stack is being unwound by unhandled exceptions in your PLSQL code. This is a catch-all error for PLSQL exceptions and is commonly seen. Ora-06512 does not indicate the actual error, but … Continue reading How to resolve ORA-06512 at line num »

Top 40 oracle dba interview questions and answers

Last updated on April 1st, 2017 at 10:36 amThis article contains the most commonly asked top 40 oracle dba interview questions and answers 1) What is oracle database ? Answer: Oracle Database is a relational database management system (RDBMS) which is used to store and retrieve the large amounts of data. Oracle Database had physical and logical structures. Logical structures and physical structures are separated … Continue reading Top 40 oracle dba interview questions and answers »

Useful Unix command for Oracle DBA

Last updated on November 27th, 2016 at 08:38 am Oracle DBA need to operate on Unix/Linux/Solaris/AIX Operating system. He has to locate various file, process, kill session ,clear directories, schedule cron and various other activities. Here in this article I am trying to give some Useful Unix command for Oracle DBA  to help them in day-to-day activities.These same commands are applicable for Linux also. Hope you … Continue reading Useful Unix command for Oracle DBA »

ORA-00911: invalid character Common Issues and Resolution

As per OERR,ORA-00911: invalid character Cause: identifiers may not start with any ASCII character other than letters and numbers. $#_ are also allowed after the first character. Identifiers enclosed by doublequotes may contain any character other than a doublequote. Alternative quotes (q’#…#’) cannot use spaces, tabs, or carriage returns as delimiters. For all other contexts, consult the SQL Language Reference Manual. Action: None ORA-00911 exception … Continue reading ORA-00911: invalid character Common Issues and Resolution »

ORA-03113: end-of-file on communication channel

ORA-03113 is a quite a common error.Let us take a deep dive into it Issue ORA-03113: end-of-file on communication channel Cause: The connection between Client and Server process was broken. It may also happen if the external agent extproc crashes for some reason. Action: There was a communication error that requires further investigation. First, check for network problems and review the SQL*Net setup. Also, look … Continue reading ORA-03113: end-of-file on communication channel »