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 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

This 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 the datatype that we are all familiar with … 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

This 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 from each other 2) What is the difference … Continue reading Top 40 oracle dba interview questions and answers »

Useful Unix command for Oracle DBA

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 like it   How to kill all similar processes … 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 »