Oracle is a RDBMS (Relational Database Management System) created by Oracle Corporation. It supports a large number of languages and application development frameworks. Its primary languages are SQL, PL/SQL and Java. Also included is support for C (Pro*C, OCI and EXTPROC), C++ (OCCI) and Java (JDBC) ...

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What storage engines work with Oracle?

http://en.wikipedia.org/wiki/Database_engine mentions about database engines aka storage engines. What all storage engines can be used with the Oracle database?
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Is Oracle free to download?

I am a Java developer and currently I use PostgreSQL as the RDBMS. However, I would also like to learn Oracle. So can I download a latest version of Oracle (11g I guess) for free? I found this link: ...
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How the indexes are managed?

I am trying to understand how the indexes are managed for below common data types: 1- Numeric (Integer, Decimals) 2- String (Varchar, Char) 3- DateTime I have few questions: 1- How the indexes are ...
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For Oracle, we mount the instance to the database or mount the database to the instance?

The following text is extract from oracle documentation. Start the instance, and mount and open the database. This can be done in unrestricted mode, allowing access to all users, or in ...
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PL/SQL: best way to count elements in an array?

Given this: DECLARE TYPE T_ARRAY IS TABLE OF VARCHAR2(2000) INDEX BY BINARY_INTEGER; MY_ARRAY T_ARRAY; V_COUNT INTEGER; I would like to do: BEGIN -- ... some code filling the MY_ARRAY ...
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How to get rid of ORA-28002 message the password will expire within 6 days?

I have a user getting an ORA-28002 indicating that the password will expire within six days. I ran the following: ALTER PROFILE DEFAULT LIMIT PASSWORD_LIFE_TIME UNLIMITED; But when I try to log ...
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Defining constraints in `CREATE TABLE` statements

Recently I have been using a Database Abstraction Layer built by a Python web-framework called web2py (click for their DAL syntax). They include the option to include your constraints within the ...
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SQL Server Express vs. Oracle Express Edition vs DB2 Express-C

I have been trying to compare the features of the SQL Server Express, Oracle XE and DB2 Express-C, but find it difficult to compile all the differences into one place. Especially the current ...
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Why do we need to backup Oracle archive logs along with datafiles

Oracle® Database Backup and Recovery Basics 10g Release 2 (10.2) says that Archived redo logs are the key to successful media recovery. Back them up regularly. But, I wonder, why backups of ...
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Why I don't need to COMMIT in database trigger?

We can't COMMIT/ROLLBACK in DML triggers because transaction is handled manually after DML statement. However, database triggers seems to be an exception. For example, suppose there's a database ...
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Replicating only changes made by a specific database user

I am performing parallel testing. We have upgraded the legacy batch jobs to a new framework which we need to test against the existing batch jobs. In the existing setup, I have web application which ...
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Alternative for OPTIMIZER_FEATURES_ENABLE

I've installed a PHP driven application in a client's 9i server (Oracle9i Release 9.2.0.1.0 - 64bit Production). Certain queries are having an awful performance (it can use from 15 minutes to hours ...
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Database replication and consistency check

I got a question about 2 databases (oracle 10g) that I have, let's call them A and B. A have some information(in various tables) and I want B to get a partial copy of some tables from A, and ...
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Building Dynamic Oracle Where Clause

I'm working on application that uses dynamic query to do a select statement based on user input, after discussing security with DBAs they want me to convert my dynamic select statement into Stored ...
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1answer
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What is “SAP on Oracle”

OK, total newb question. What is "SAP on Oracle", exactly. This link is talking about how SAP can run on Oracle (I think). I'm not understanding how this is working. My understanding: SAP is a ...
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Oracle Enterprise Manager 11g dbconsole “Internet Explorer cannot display the webpage”

The dbconsole is configured and started, but when I navigate to it, Internet Explorer shows the page stating that "Internet Explorer cannot display the webpage". This is the error that means that IE ...
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If an 'after' DDL trigger causes an error, is the DDL rolled back?

It has been suggested that DDL is logically performed something like this: begin COMMIT; perform any appropriate pre-DDL trigger code; do the ddl; perform any appropriate post-DDL ...
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Oracle clean up

I have an Oracle database on a VMWare image that seems to be slowly eating all my available disk space. I would like to know if there is a command or script that would perform some kind of clean up of ...
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What could be the reason for disallowing a sub query in the values clause?

For example SQL> create table dates(d date); Table created. SQL> insert into dates select sysdate from dual; 1 row created. SQL> select * from dates; D --------- 28-MAY-11 SQL> ...
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What methods are available to create a snapshot of an oracle database for testing purposes?

I am new to databases and have just been assigned to work with Oracle. We want to create a snapshot of the database for testing purposes that will allow us to revert back once we're done. I'm a bit ...
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How to retrieve foreign key constraints data

I'm looking for a query allowing to retrieve foreign key infos (each line: referrencing table & field, referrenced table & field) of an entire schema. I've found this, but does not gives all ...
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How do I allow users to see grants, view definitions, PL/SQL, etc in a database without granting them access to change those objects

As a developer, I need to be able to access the design of the database/database objects from production so I can ensure I'm working with the latest and greatest version of the objects I'm developing ...
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Why does the CBO not chose a lower cost skip scan without stats?

In the script below, the CBO chooses an INDEX FAST FULL SCAN over an INDEX SKIP SCAN (this is illustrated by the queries with the UNION ALL but you can demonstrate it is true with just explain plan ...
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Bulk database update/insert from CSV file

I am implementing application specific data import feature from one database to another. I have a CSV file containing say 10000 rows. These rows need to be inserted/updated into database. There ...
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Cardinality rule for bitmap indexes

The Oracle documentation includes the following advice: A bitmap index should be built on each of the foreign key columns of the fact table or tables In that reference, there is even a bitmap ...
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Retrieve Indices of Associative Array as Collection

In PL/SQL, suppose I have some associative array defined as follows: declare type a_arr_t is table of PLS_INTEGER index by PLS_INTEGER; a_arr a_arr_t; I then, sparsely, populate the ...
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Session in “Sql*net message from client”, but is active

I've Googled around, and my impression is that Sql*net message from client suggests the Oracle DBMS is waiting for the client to send new commands to the DBMS, and therefore any time spent in ...
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Restricting database access per IP addresses

I have filtered IP addresses to an access DB server like this: Set the sqlnet.ora tcp.validnode_checking = YES tcp.invited_nodes = (localhost, 192.168.100.130, 192.168.100.186) But in my ...
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Oracle Advanced Queuing LIFO

With Oracle's Advanced Queuing is there a way to dequeue messages in a LIFO (last in first out) order? There is an indication through a lack of information that this is not an option, but perhaps ...
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Oracle partition by interval using persian calendar

Oracle supports Persian (Jalali) calendar in DDL queries, I can easily say: select to_char(register_date, 'YYYY-MM-DD', 'nls_calendar=persian') from my_table; I created a table as: create ...
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1answer
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Importing schema to new or different tablespace

Is there a convenient way to import a schema into Oracle 11gR2 using a single new or different tablespace than where the data originated? As an example, I have exported BLOG_DATA from OLDDB, where ...
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What is the easiest way to move data from Oracle to SQL Server?

One of our products supports both Oracle and SQL Server as database backend. We have a customer who wishes to switch from an Oracle backend to Microsoft SQL Server, which isn't a typical transition ...
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Oracle: DB *partial* constraint?

I am pretty new to Oracle and the database world. I am not sure if the title makes any sense at all, so I'll just go ahead and explain my situation. I currently have a table at hand that records ...
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Product of n Rows

From this data (assuming the number of rows is not known in advance): with q1 as (select mod(ora_hash(level),5) c1 from dual connect by level <=4) select * from q1; /* C1 -- 2 1 4 1 */ I ...
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ORA-04031: unable to allocate bytes of shared memory (“”,“”,“”,“”)

I am receiving this error in a development database. It happens on some specific queries (simple inserts and deletes via .NET application). The database is used by one user, and error happens ...
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1answer
547 views

Are there performance benefits to turning off archivelogging? Is it wise?

The first part of the question is pretty simple; has anyone run a DB in both archivelog and noarchivelog mode? Were there any measurable performance benefits to turning off logging that you could ...
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How do you show SQL executing on an Oracle database?

How can you show the SQL that is currently executing on an oracle db? Extra information that would be useful would include user, session id etc.
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1answer
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Oracle RAC failover not working correctly

I have Oracle 11gR2 set up on a RAC environment with two nodes. I have SCAN set up, eg: I have two entries on the DNS set up so I can ping the SCAN name and reach either node. I can also ping both ...
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1answer
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Do I need to enumerate the columns used in a materialized view when creating the MV log?

I'm currently creating materialized view logs on a whole bunch of tables in order to support materialized views with FAST REFRESH. The materialized views we're creating contain approx 30 columns from ...
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How do I find an object that doesn't seem to exist in the objects table?

I have an object called cot_ntn_pi_v. I was told this was a synonym. It doesn't appear in the all_synonyms table. It looks like a view or table but I can't find it in the all objects table. I can ...
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Database logon trigger

To block a particular user and IP combination on an Oracle Database , I created the following trigger, and compiled without errors. Create or replace trigger you_may_not_login after logon on database ...
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1answer
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Oracle 10g express database link to Oracle 8i

I upgraded a 9i install to 11g with only one problem. Database links between 11g and our legacy 8i database are no longer supported. I have to transfer data from 11g to 8i two or three times a day ...
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Gathering information to tune oracle row prefetching

I'm trying to determine a value for the number of rows an oracle client will prefetch (i.e. OCI_ATTR_PREFETCH_ROWS, exposed as setFetchSize in JDBC) that will minimize the number of server round trips ...
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1answer
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DBA's Scope in datawarehousing Projects

As a DBA trainee, what needs to be known in order to be part of datawarehousing projects? I mean what resources are suggested to have an overview knowledge of how PL/SQL and other concepts are used ...
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1answer
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Case Behavior Changed Between 11.2.0.1 and 11.2.0.2

I have a case open with Oracle and they say they can't reproduce this. Running the following in 11.2.0.1 or lower produces two rows from both of these queries, but in 11.2.0.2 the second query ...
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Bad use of Oracle Tablespaces

I have a doubt about the use of oracle tablespaces. I've decided to define for each schema of the datababase two different tablespaces (one for data, and another one for indexes). The problem is that ...
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Oracle View Ignoring External WHERE Clause

Good day, This one has me stumped. I have a rather nasty developer query that I would like to store in a non-materialized Oracle view. The text for the view itself is a bit long to list here, but ...
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1answer
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Oracle aggregate functions slows query down massively

I have a table with ~12M rows of data in it. Here is the table structure: SYSTEM_ID BATCH_ID MEASUREMENT_INDEX, PARAMETER_ONE, PARAMETER_TWO The primary key is made up of the first three columns. I ...
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1answer
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How can I get the Oracle TNSListener to start after changing my host name?

When running lsnrctl status I can see that it is using the old host name, but I don't know where it is pulling that value from. My Oracle installation is 11.2.0 on Windows7 x64, if that makes any ...
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How to troubleshoot enq: TX - row lock contention?

I have the following situation. I have RAC. On both nodes there are the locks. On the First Node SID EVENT USERNAME BLOCKING_SESSION ROW_WAIT_OBJ# OBJECT_NAME ...