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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SQL ANSI JOIN precedence

I have a query that looks like this: SELECT * FROM TBLA A LEFT JOIN TBLB B ON A.Col1 = B.Col2 RIGHT JOIN TBLC C ON B.Col3 = C.Col4 JOIN TBLD D ON C.Col5 = D.Col6 In which order ...
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1answer
2k views

Why does an Oracle database require both the SYSTEM and the SYSAUX tablespaces?

Quoting from Oracle documentation about logical storage structures: A database must have the SYSTEM and SYSAUX tablespaces: Why is it compulsory to have these tablespaces?
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2answers
21k views

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 ...
6
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1answer
2k views

What's the difference between a v$ view and its dba_ equivalent?

What's the general difference between a v$ view and its dba_ equivalent? Take, for example, v$tablespace and dba_tablespaces.
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2answers
562 views

Can Oracle be installed on Windows without being an administrator?

Can the oracle software be installed on windows without having administrator privileges?
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3answers
861 views

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 ...
6
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1answer
3k views

When is an application using too many sessions?

I'm working on a client-server application that uses OCI to communicate with Oracle. In the past our application often treated sessions as an infinite resource, quite possibly to the detriment of ...
6
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1answer
45k views

How to transfer data using expdp and impdp commands?

I'm Oracle noob, and my intention is to transfer all data and metadata from one schema to another schema within an Oracle database. I'm planning to use datapump expdp and impdp commands. I have ...
6
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2answers
29k views

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 ...
6
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1answer
91 views

Why are some aggregates treated differently in the RHS of a rule in the model clause?

With my limited understanding of the model clause, I'd expected the following three queries to return the same results because there are no nulls in the data, and the functions are equivalent: select ...
6
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2answers
380 views

Is it worth partitioning a Table by single value in Oracle?

Normally, if you have a column you frequently query a table by, you ought to stick an index on it. But is it worth also partitioning a table by this column, if all possible values are known in ...
6
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2answers
13k views

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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1answer
244 views

Can I use Oracle Standard or Enterprise edition for my own training purposes?

Question is about Oracle licensing terms. I would like to learn more about Oracle Database administration. Unfortunatelly I am using 32 bit verison of LInux, so I can't install Oracle 11 XE (I can't ...
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3answers
2k views

Why performance degradation with query hint FIRST_ROWS(1000)? [closed]

I have a query with user supplied arguments that can produce a very high amount of rows depending on the user's input. In case the user supplies very unselective arguments, the query takes a lot of ...
6
votes
1answer
17k views

PLS-00306 Error: How to find the wrong argument?

PLS-00306: wrong number or types of arguments in call to 'string' Cause: This error occurs when the named subprogram call cannot be matched to any declaration for that subprogram name. The ...
6
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1answer
6k 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 ...
6
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1answer
662 views

sqlplus consuming 99% CPU

Oracle's installed on one server, I'm running sqlplus on a different (application) server. I've recently encountered a problem getting sqlplus to do anything; it simply spins, consuming 99% CPU even ...
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2answers
334 views

Exporting database Oracle 7.3 on Windows NT 3.51

How to take dump files on Oracle7.3 running on Windows NT 3.51? Should you stand in the Orant/bin folder and run one of the programs there like> exp73 SYSTEM/password@[dbinstance] FULL=Y ...
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3answers
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Is it possible to see the (completed) SQL Statements executed by a specific session?

Is it possible to see a list of all past SQL statements executed by a specific session (or number of sessions)? For example, the following query gives me all currently executing statements from all ...
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3answers
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ALTER SYSTEM DISCONNECT SESSION doesn't work

Oracle 11g. The devs leave sessions connected overnight, sometimes certain cron jobs fail because of that. I am trying to kill all user sessions, but I can't. I login as: sqlplus system/[password] ...
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2answers
1k views

Making the Oracle optimizer use a virtual column to find out about a partition

I have a large table that has three columns like this: "START_DATE" DATE, "START_VALUE" NUMBER(10,7) "START_DATE_VALUE" NUMBER(18,7) GENERATED ALWAYS AS ( (extract(YEAR FROM START_DATE) * ...
6
votes
1answer
2k views

MySQL or Oracle Associate Certification?

I have 15+ years in software development and 7+ in web development, and I want to get a certification in another area, like DBA. I have 7+ years of experience like MySQL developer. Which is better for ...
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3answers
4k views

Add Oracle Label Security to an existing Oracle installation

We are using Amazon EC2 to host some Oracle database instances while we are evaluating and prototyping some software. We are using the AMIs provided by Oracle - specifically, Oracle Database 11g ...
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2answers
91 views

What is an Oracle ASSEMBLY?

What is an Oracle ASSEMBLY, in the context of Oracle SQL? It's listed in GV$SQLCOMMAND. Although GV$SQLCOMMAND is not a perfect guide to "real" SQL statements - for example it has UPSERT instead of ...
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1answer
282 views

What are the Oracle Dataguard Implications of Migrating to a PDB?

If I have an OLTP database with two physical standby instances (one remote) what are the implications of migrating the primary DB to being an Oracle 12c PDB? i.e. Does the process of migrating to ...
6
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1answer
385 views

Sudden increase in log_file_sync waits

I'm on Oracle 11gR2 with a 2 node RAC system. It's shared fiber storage to an EMC Clariion. Last friday things went bad..fast. All of the sudden processes that normally ran fine for years became ...
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1answer
14k views

How to free up disk space? which logs/directories to clean?

I want to free up the disk space on my Linux machine. I've drill down the space usage and found that the following directories have a big size /u01/app/11.2.0/grid/cv/log ...
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1answer
1k views

Global locking for multi-master Oracle GoldenGate replication

This is a very complex scenario, but I figured a state-of-the-art challenge might interest some of the many high-end users of dba.se. Problem I'm working on an intercontinental data replication ...
6
votes
1answer
744 views

Package state not re-intialized on raise_application_error

When a package has state and the header is changed, the first call gets an error stack something like this: ORA-04068: existing state of packages has been discarded ORA-04061: existing state of ...
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2answers
3k views

SQL developer: Setup debugger for plsql

I'm trying to debug remotely pl/sql. But I can't - database returns me an error. What should I do to fix this and start debugging ? ORA-30683: failure establishing connection to debugger ...
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0answers
177 views

9i streams capture doesn't evaluate rules

I have a streams replication set up between two oracle 9.2.0.8 instances as sources and an 11g instance as a destination, processing a small subset of data from each database (let it be one table ...
6
votes
1answer
1k views

What is the meaning of “select * from relational(owner.table)”?

We recently got some errors in our alert log of the form 301598: Tue Jul 16 03:58:29 2013 301599: ORA-01555 caused by SQL statement below 301600: SELECT * FROM ...
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votes
3answers
1k views

Alternatives to an INSERT Trigger

Looking for an example code in Oracle to do the same. i.e. Remove an insert trigger on table T1 whose job is to create a row in T2 based on the derived data. How would this PL-SQL api look like? ...
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6answers
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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: ...
5
votes
3answers
639 views

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 ...
5
votes
2answers
191 views

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 ...
5
votes
1answer
3k views

how to use dual foreign key in oracle 10g

I have created two tables create table ref1(id varchar2(3) primary key); create table ref2(id varchar2(3) primary key); Now I want to create a third table with a single column as foreign key for ...
5
votes
2answers
12k views

What is Key Preserved Table concept?

I read in the Oracle Documentation about key-preserved table in Updating Join Views Section. However, I didn't find any simple to way understand it. I hope to receive some simple conceptual details ...
5
votes
2answers
8k views

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 ...
5
votes
2answers
550 views

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 ...
5
votes
1answer
7k views

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 ...
5
votes
3answers
569 views

What are the top 5 design decisions which need to be made when implementing a database?

I am implementing an Oracle System to store event alerts from an application so I guess all the schema, database design will be handled by the application through a sript. I am new to Database ...
5
votes
4answers
11k views

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 ...
5
votes
4answers
173 views

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 ...
5
votes
4answers
241 views

What's the best way to list groups of values that are contained in other groups

For example, starting with a table like this: create table t as select 'A' as x, level as y from dual connect by level<=5 union all select 'B' as x, level+2 as y from dual connect by level<=5 ...
5
votes
3answers
836 views

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 ...
5
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3answers
797 views

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 ...
5
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2answers
22k views

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 ...
5
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3answers
7k views

Trouble killing sessions then immediately dropping users in Oracle 11g XE

I would like to be able to kill active sessions by a given user, and then drop that user, and do so within a single database call. Here is what I have so far: DECLARE cursor c is select * ...
5
votes
1answer
551 views

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 ...