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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Query execution time in Oracle SQL Developer

I know I can use set timing on to see how long it took to execute a query after the execution is finished. But is it possible to see current execution duration in Oracle SQL Developer while the query ...
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What features of Oracle make it an attractive choice for small projects?

Given Oracle's licensing handling[a] (and, to a lesser extent, cost) I have always been wondering what the deciding factors would be for choosing Oracle over PostgreSQL or MySQL. My company is nearly ...
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1answer
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What does TOAD do, when I terminate script execution?

When it stops the execution of a long running script. The script terminating needs even longer then the time the script was running. I.e. I have to kill Toad. 2nd EDIT: Just found that this is a ...
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hierarchical query in oracle

Suppose I want to perform data migration operation for which I would like to load the parent tables first and then the child tables for the obvious reason. Some of these tables play dual role. Assume ...
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DROP PARTITION strategy using LIST-REF composite partitioning

We have a large Oracle 11gR2 instance with some tables that have recently become an annoyance when deleting data. This database powers a large optimization cluster that takes input metadata from the ...
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2answers
474 views

Use different Windows account in pl/sql

Is it possible to use/log in to a different account in pl/sql. For example, I would like to write to a file in a folder only a specific account has access to. Here's an example of what I mean: Other ...
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2answers
732 views

MAX for each subset

I have a table that looks like this: +---------------------------------------------+ | EVENT_ID | ITEM_ID | PERSON_ID | EVENT_DATE | +---------------------------------------------+ | 123 | 1 ...
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2answers
558 views

Encountering exception ORA-01555

I was given a problem to solve , in which there is table called Scenarios in the Master Db which contains the details of all the Tablespace for which I have to find the size. The O/P should contain ...
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3answers
424 views

Huge Data Migration in Oracle and space concerns

I am trying to do Insert append as part of data migration from SchemaA.table1 to SchemaB.table2 in the same Oracle database. Due to refactoring of Table2, there will be some form of data ...
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1answer
531 views

Recover Oracle database after drive loss Interview Question

How would you answer this as an interview question? The database crashed and you lost a drive containing one of your control files and another drive containing an entire redo log group. You ...
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3answers
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Can Oracle row-level security work with user session credentials?

Can row-level security in Oracle be controlled by a user's session credentials or user context? Here's an example to illustrate what I'm looking for: Our database contains a bunch of sensitive ...
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1answer
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What are the pros/cons of Oracle's Grid Control compared to DB Control?

Database control is a web based tool for managing a single Oracle database that is installed on the same box as the database itself. Grid Control is a web based tool for managing multiple Oracle ...
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1answer
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Oracle implicit parameter casting - why doesn't it always work? (ORA-06502 error)

I have a Java (Spring) app that uses Oracle 10 as DB. Some legacy code has wrong parametrization of PL/SQL procedures. For instance, some input parameters are declared as OracleTypes.VARCHAR in Java ...
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2answers
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In Oracle, can we restore a database onto the same instance with a different name?

In SQL server I can restore a database onto the same instance with a different name. Eg: If there is a database DB_prod, I can take a full backup and restore it on the same instance with a different ...
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3answers
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How to connect to a remote Oracle server from Windows machine using PL/SQL Developer?

I understand that I need to configure database address in the TNSNAMES.ORA file but where should I put this file? UPDATE I defined the $TNS_ADMIN variable, created the TNSNAMES.ORA file, added new ...
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2answers
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Current isolation level in oracle

How to get the current (default) transaction isolation level in oracle?
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2answers
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Does the target for Double-Take replication require an Oracle license? [closed]

Where would Vision Solution's Double-Take product fall with regard to Oracle Licensing? It is both a backup and a replication of the database. Oracle's Software Investment Guide has a section on ...
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2answers
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Is Oracle DB licensing needed for a test environment?

I'm planning to setup an Oracle Standard Edition instance on a server in our test environment. Do I need to purchase a license for this?
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1answer
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Oracle 10.2.0.1.0 listener process stopped

When I am checking my servers I see that there is an error about listener process stopped. I logged in and checked the status of listenere. please see the below status; LSNRCTL> status Connecting ...
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3answers
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How to convert a Top 1 subquery using outer table alias to Oracle?

I have the following SQL Server query select (select top 1 b2 from BB b where b.b1 = a.a1 order by b2) calc, a1, a2 from AA a where a2 = 2; which I can rewrite using analytic functions ...
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1answer
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How do I horizontally partition an oracle database table, and should I?

We have a tenanted data warehouse that we are doing reporting on. Queries are beginning to take a long time, and we're looking at options to reduce this. There are two thoughts at the moment. Create ...
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7answers
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How do I Create Tablespace in Oracle 11g?

I am not too savvy in Oracle, and I have been trying to create a TABLESPACE, which keep on giving me an error message of invalid file name. Below is the syntax that I have used: SQL> create ...
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1answer
216 views

When refreshing materialised views does the index automatically refresh

When refreshing materialised views does the index automatically refresh
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1answer
918 views

Materialized views in oracle

How are materialized views implemented in oracle? I've created a materialized view in oracle. What I now see is a quite normal table with a job. Are materialized views translated into tables & ...
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1answer
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Oracle materialized view refresh schedule

Since I see that it is possible to specify an expression like sysdate + 1, here are my questions: Is it possible to specify the exact time of the refresh for materialized views in oracle? Is it ...
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1answer
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Running a stored procedure across db Link

I have a script whose sole propose is just to transfer data from one schema to another via a db link. Part of the process however is that after the data has been loaded, a stored procedure needs to be ...
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2answers
706 views

Resources for SQL Server developer migrating to Oracle

What resources can you recommend for a SQL Server developer wanting to learn Oracle basics? I am looking for a comprehensive whitepaper or blog post describing differences between these systems and ...
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Rebuild large Oracle 10g index with insufficient TEMP space?

One of my (Oracle 10g) tables has grown over time to about 840 million rows. An index (DATE, NUMBER(38)) on it occupies 38GB at present. I'd like to change the index (I think it could make good use of ...
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1answer
246 views

Can I use dbms_redefinition with bulk data transformations for better results?

Here is a situation for bulk loading in Oracle: Schema A { T1, T2, T3, T4} Schema B { TR1, TR2} Where schema B is re-factored from schema A. Both exist in same DB. Schema A has terabytes of ...
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2answers
408 views

How to create a user with a particular user_id?

Is it possible to specify the user_id of a user while creating it? SQL> create user user1 identified by user1; User created. SQL> select user_id, username from all_users where ...
3
votes
1answer
944 views

Oracle query against SQL Server database giving inconsistent results

We have multiple Oracle 11.2.0.2 databases with og4odbc database links to a SQL Server 2008 database. A particular table in the SQL Server database has two Varchar(36) columns. The following ...
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1answer
225 views

Why am I not seeing any benefits of parallel execution when parallel clause is used?

I have these two methods of creating a table and populating with rows. The first one uses a parallel (degree 3) clause, so I expected the inserts to be much faster. But I timed the time taken for a) ...
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3answers
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How do indices impact query performance?

Obviously keeping several different indices has a negative impact on insert and delete performance. How about query performance: Does it make sense at all keeping too many indices on a table? Will the ...
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2answers
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How to migrate SQL Server Stored Procedures using temporary tables or table variables to Oracle?

C# developer encouraged by management to write SQL Server stored procedures often produce procedures like this create table #t1 (...); insert into #t1 Select ... from table_a where ...; insert into ...
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1answer
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DBMS_Resource_Manager.Calibrate_IO Usage

DBMS_Resource_Manager has a procedure called Calibrate_IO with a Physical Disks input parameter. The documentation says this value should be set to the... Approximate number of physical disks in ...
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2answers
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Index vs. partition

Why is it not possible to achieve performance improvements with indexes only, so that other techniques like table partitioning becomes necessary? The question relates only to performance, of course ...
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2answers
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DBMS_REDEFINITION vs EXCHANGE PARTITION in oracle

In order to partition an existing non-partitioned table it is possible to use either the EXCHANGE PARTITION or DBMS_REDEFINITION. How to decide on which of those possibilities to choose for table ...
6
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1answer
7k views

Introduce partitions into an existing non-partitioned table

What has to be done to introduce range partitions into an existing non-partitioned table in oracle? Is there an easy to do and safe way to do this? Especially in cases where there are many ...
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2answers
559 views

large data movement

I would like to move billions of rows from schema1.table1 to new schema2.table2 where table2 is a refactored one from table1. Hence their table structure is different. both table1 and table2 are ...
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vote
1answer
575 views

Drop Oracle data file with 0 bytes and in offline (needs recovery) state

What can I do to drop a data file mistakenly created and currently with 0 byte and in offline (needs recovery) state?
3
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1answer
4k views

Optimal value for LOG_BUFFER parameter

The wait event “log buffer space” according to the documentation can indicate that the log buffer is too small or the I/O is slow. We have a system seeing this event in which the redo buffer ...
6
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1answer
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Why does SQL*PLUS need a slash after CREATE TYPE?

I just had the problem that I defined a Type and tested it in TOAD and all was OK. But running under SQL*PLUS it threw an error. Example: CREATE OR REPLACE TYPE MyType AS OBJECT ( Item1 NUMBER, ...
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1answer
488 views

oracle monitoring db status

I am looking for a way to monitor Oracle Database status (health) via PHP script executing SQL query. There are system variables containing actual number of connection, sessions, work load, etc... ...
3
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2answers
386 views

Searching for a Data Dictionary for SQL or Oracle

I am looking for metadata specifications (data dictionary) for SQL Server and Oracle databases. By metadata map, I mean a definitive description of what objects make up database model and their ...
4
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2answers
2k views

Updating rows conditionally with a gapless ascending value

A user has a table they would like to update. Depending on the data in other columns they want a particular column to be updated with an ascending value starting from 1 that is gap-less. The rows ...
2
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1answer
1k views

database duplication VS database replication

Is there a difference between duplication and replication with reference to a database? I am not sure if I am correct at all, but duplication means to me that we are copying bit by bit without ...
2
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2answers
11k views

SGA_MAX_SIZE and SGA_TARGET

We recently increased sga_max_size to 4g from 2g but didnt increase sga_target, is it ok not to increase sga_target?? reason we wanted to increase sga is to reduce wait time on sequential reads in our ...
2
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2answers
3k views

What does 'nls' in nls_date_format stand for?

For example: alter session set nls_date_format = 'DD-MON-YYYY hh24:mi:ss'; changes the date format for the session. What is nls here?
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3answers
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Multiple Oracle Instances — is this a good practice?

One of my clients has deployed our product's db into a Solaris machine which already has 3 instances of Oracle. So, right now there are 4 instances of Oracle running on the same machine. And now we're ...
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1answer
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Is there any tool to convert Oracle commands to MySQL?

Is there any tool which I can use to convert Oracle commands to mysql commands?