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

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 »

How to resolve the ORA-00257 error in Oracle database

ORA-00257 is one of the commonest error in Oracle DBA life. He/She often has to deal with it.Database almost got frozen because of it and all transaction get stopped .Let us see how to deal with ORA-00257 error Error Message   ORA-00257: archiver error. Connect internal only, until freed. As per The oerr ORA-00257 error means ORA-00257: archiver error. Connect internal only, until freed. Cause: … Continue reading How to resolve the ORA-00257 error in Oracle database »

How to resolve ORA-29913 with external tables

ORA-29913 is one of the common error when working with external tables in Oracle database. We would be looking at various ways the error can be produced and what can be done to resolve the error External File not found or permission incorrect SQL> select * from Scott.example_external_table; select * from example_external_table * ERROR at line 1: ORA-29913: error in executing ODCIEXTTABLEOPEN callout ORA-29400: data … Continue reading How to resolve ORA-29913 with external tables »

Top-N Queries and Pagination

Top-N Queries  and Pagination is common in Web-based applications. The user inputs a set of criteria, which runs a query and then lets the user click the Previous and Next buttons to page through the result set. To achieve this paging functionality, the application needs to be able to get a certain set of rows from the Database query. Lets take a look at the … Continue reading Top-N Queries and Pagination »

Top 10 Useful Queries for Flashback Database

Introduction to Flashback Database .It is faster than traditional point-in-time recovery. The traditional recovery method uses backups and redo log files; Flashback Database uses a new type of log file called the Flashback Database log. The Oracle database server periodically logs before images of data blocks in the Flashback Database logs. The data block images are used to quickly back out changes to the database during … Continue reading Top 10 Useful Queries for Flashback Database »

Oracle Flex Cluster 12c

With 12c, Oracle has introduced Oracle Flex cluster.Oracle Flex cluster 12c is a new Oracle Clusterware based High Availability clustering topology It Utilizes two types of cluster nodes: Hub nodes Traditional nodes, tightly coupled via network and storage, used for running IO intensive workload Leaf nodes Leaf Nodes A new type of node that runs a lighter weight stack Maintain their own failure and heartbeat … Continue reading Oracle Flex Cluster 12c »

Online move of active datafile in 12c

Last updated on October 11th, 2016 at 06:24 pmFor rename and  relocation of datafile in pre 12c release, we need to put the tablespace in offline mode  then do the movement and then bring it online again. So  it was a offline task with number of task to perform With 12c R1  , a data file movement  no longer requires a number of steps i.e. put … Continue reading Online move of active datafile in 12c »