Category Archives: Oracle

ORACLE TUTORIALS

Oracle is most widely used Oracle database in the world. It has the capacity to handle large database and high transaction

Here I am presenting the Oracle tutorials on Various Oracle products

  1. Oracle database
  2. Oracle sql/plsql
  3. Oracle application
  4. Weblogic
  5. Performance tuning.

These articles will be  really help in understanding the oracle products and getting started on Oracle system

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 »

copy directory linux command examples

While working on project/development in Linux operation system , we often need to  backup the current working folder i.e copy directory .  We will be seeing here various ways to copy directory linux. Linux Operating system provides cp command to copy the files/directory from one place to another  and mv command to move the file/directory.I would explaining each command in details here with many examples … Continue reading copy directory linux command examples »

ORA-00001 unique constraint violated

ORA-0001 unique constraint violated is one of the common message we often get while loading data. This error occurs when You tried to execute an INSERT or UPDATE statement that has created a duplicate value in a field restricted by a unique index. We can perform following action items for this error  You can look at the error and find the constraint information with the below sql … Continue reading ORA-00001 unique constraint violated »

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 the ORA-00936 missing expression

ORA-00936 missing expression is one of the common error everybody working in Oracle sql must have faced some time. This generally happens when you omit important thing in the sql statement i.e you left out an important chunk of what you were trying to run Reference : Oracle documentation This Oracle error is mainly related to the SQL SELECT statements. One obvious reason is select column … Continue reading How to resolve the ORA-00936 missing expression »

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 »

Oracle PLSQL Tables

PLSQL tables are composite datatypes. These behave in the same way as arrays except that have no upper bounds, allowing them to constantly extend. They are also called index by table PLSQL Table contains two elements 1) A primary key of BINARY_INTEGER datatypes that index the table, which do not need to be consecutive. The collection is extended by assigning values to an element using … Continue reading Oracle PLSQL Tables »

Everything about Oracle PLSQL records

Oracle PLSQL records PLSQL records are composite datatypes .It is a group of related data items as fields ,each with its own name and datatype. PL/SQL records are similar in structure to a row in a database table. Each scalar data types in the record holds a value. A record consists of components of any scalar, PL/SQL record, or PL/SQL table type. They can be … Continue reading Everything about Oracle PLSQL records »

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 »

Top 40 Oracle sql interview questions

This article contains Top 40  Oracle sql interview questions asked in various interview. I hope it should help in interviews 1) What is a table Cluster ? Answer: Table Cluster is a group of related tables that share common columns are store related data in the same block. 2) What is exists usage in sql Answer “exists” statement helps us to do the job of … Continue reading Top 40 Oracle sql interview questions »