Ask the Experts
Ask the Experts
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Using OS Authentication
I believe that we have a configuration somewhere (Oracle?) that allows Unix user account "ORAsid" to connect to the database as "OPS$ORAsid" without requiring a password. Is this true? Could this be changed (to requiring a password to get into the ... Continue Reading
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Converting from CHAR to DATE datatype
As a time value, I used the CHAR datatype and need to convert to a DATE value while manipulating/computing. How do I use the DATE datatype instead? Continue Reading
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Input/output errors
I have the following error:
ERROR at line 1: ORA-01115: IO error reading block from file 2 (block # 2772) ORA-01110: data file 2: '/home5/oracle/oradata/lrec_ts_files/lrec.dbf' ORA-27091: skgfqio: unable to queue I/O ORA-27072: skgfdisp: I... Continue Reading
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Migrating from Solaris to Linux
We need to migrate our Oracle 9.2 database from Sun Solaris to Red Hat Linux. Our datafiles are stored on EMC's SAN. Do we have to use export and import even though we use a centralized storage? Continue Reading
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Fatal NI connect error
I have the following error in my Oracle server: "Fatal NI connect error 12638." I don't understood why because it was working so well before, but today it sent that error. Continue Reading
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Database crash during hot backup
Our Oracle 8.0.4 database crashed while doing a hot backup with CA BrightStor. Now one of our databases will not start. Event viewer shows it starting and then shutting down again. Our dbaora7.log shows that all tables and control files ... Continue Reading
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Installing 32-bit and 64-bit Oracle on same machine
I have an application that does not support 64-bit Oracle. It needs to run on 32-bit Oracle. Can I install two Oracle engines (32-bit and 64-bit) on the same machine? If so, how can it be done? Continue Reading
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Three consecutive months in fiscal year
I have a conveyance_claim table with claim date and type, one record per month. I have to check in financial year (April to March) if three continuous months have claims of the same type. How can I find it? Continue Reading
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Multiple instances on a single database
Is it possible for Oracle to have parallel servers (single database, multiple instances)? Is it impossible to have the inverse (that is, multiple databases, single instance)? Continue Reading
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VARCHAR2 vs. NUMBER
What is the correct circumstance to store a numeric string as VARCHAR2 vs. NUMBER? The response I have received before is to store all numeric strings as VARCHAR2 unless the intention is to manipulate the field mathematically; but no reason has ... Continue Reading
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Concatenating XML fragments
Using XMLElement and XMLForest I have created several XML "strings." In a final XMLElement select statement with XMLForest I want to concat the earlier strings within the output of the final statement. Can concat be used within XMLElement or ... Continue Reading
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Ranking within a group
How can I get the rank of a certain column without using the rank() function, just using a simple SQL query? Continue Reading
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Receiving ORA-313 and ORA-312 errors when trying to open database
I have a cold backup of my Oracle 9i database. Recently, I tried to start it up but the database could not be opened. I decided to use the cold backup to restore the database, but the problem remained. Continue Reading
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Removing blank lines from a text file
I want to upload a .txt file containing records in an Oracle table with the UTL_FILE package. There are blank lines between two records in many places, and with the script I'm running, whenever the procedure encounters a blank line it comes out of ... Continue Reading
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Finding the SCN in the Alert Log
The Oracle documentation says you can examine the alert.log to find the SCN of the event and recover to a prior SCN. But I was unable to find any SCN in the Alert Log except the time at which I dropped my testing tablespace. Please help. Continue Reading
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How to UNION tables that are not union-compatible
Is there any way to UNION two tables that are not union-compatible? Continue Reading
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Comparing current and previous row values
My SupplyCosts table contains a list of supplies and the cost associated with that supply for every month. I want to select only the months where the cost has changed and the previous cost. SELECT DISTINCT doesn't work because I need the month ... Continue Reading
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"TNS:connection closed" error
I created a database link to link two Oracle databases. When I queried the remote database, I got "Error: ORA-12537: TNS:connection closed." How can I resolve this? Continue Reading
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Clearing the rollback segment from a tablespace
I have a rollback tablespace that shows max bytes of .30 out of 500M, with 499.69M used. I have taken my database down twice to clear the rollback segment from this tablespace and it won't go away. Is there a way to free up the space other than ... Continue Reading
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Viewing queries in v$sqlarea
I am having a problem viewing the queries in v$sqlarea. I have a procedure (p1) with lots of insert, select, update and delete statements. I am calling procedure p1 from a test procedure p2 inside a loop to have a load test for p1. But when I try to... Continue Reading
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Alternative solution to BITMAP index
I have two Oracle queries. When I do Explain Plan on these queries, they both use Index on col2 and not col1. Query1 is fast. Query2 takes over three minutes! This is the problem. I created BITMAP Index on col1 and both queries started working fast,... Continue Reading
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Data partitioning and surrogate keys
In designing a database with Oracle partitioning in mind, would it be advisable to create surrogate keys or is it better to remain with the original modelled primary key and create data partitions on the unique key (which is the modelled primary key... Continue Reading
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Loading PDF files using SQL*Loader
How do I load a PDF file into an Oracle table using SQL*Loader? Continue Reading
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Changing parameters for better performance
I have a very intensive application--4,500 transactions per second. I would like to change the table/indexes storage in order to get better performance. Continue Reading
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CLOB string too long
When you concatenate, Oracle treats a clob as a varchar2 and then, at over 4000 characters, the string becomes too long to handle. Do you have any ideas to get around this so that I can have larger HTML pages? Continue Reading
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MAX and COUNT DISTINCT
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Minimizing archive log generation
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Importing from split export files
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The disadvantages of RAC
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Converting between DMT and LMT
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Decreasing the size of the UNDO tablespace
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Displaying time, including milliseconds
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Updating rows with a cursor is slow
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ORA-01031: insufficient privileges trying to restore a database
I am logged into my database AS SYSDBA. I have to do a restore of the database. When I try to do a recovery it gives me "ORA-01031:insufficient privileges." Continue Reading
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Using the XMLElement function
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Move a row from one table to another
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Querying derived tables
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Nested functions
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Getting a count of zero for unmatched rows
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Suddenly getting ORA-01034 and ORA-27101
Question about Oracle errors: ORA-01034: ORACLE not available and ORA-27101: shared memory realm does not exist Continue Reading
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Can ETL tools handle complicated business logic?
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.dbf and .ora data files explained
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CKPT explained
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Compare last year sales to this year sales
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Calculating the next extent
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Greatest and daily challenges of a DBA
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Storing images in an Oracle database
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How Oracle unlocks deadlocks
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Removing sessions where status=killed
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Count the number of rows produced by a query
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Generating a 10 character alphanumeric sequence
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Is it possible to granting privileges on a schema level?
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Insert date from a .csv file into an Oracle table
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Script for PL/SQL jobs in automated scheduling system
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Oracle SQL vs. Teradata SQL
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Alternative to LEFT OUTER JOIN?
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Oracle application made to run in Arabic and English
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Insert records into Oracle automatically
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Joining on a substring of a column
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Sum of two table row counts as one answer
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Load data from a Microsoft Excel spreadsheet using TOAD
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Performing a backup with 24/7 availability
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Exporting a full database mode from Oracle 10g
I'm encountering error messages trying to export a full database mode from Oracle 10g. Continue Reading
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Concatenate values into comma-delimited string
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Is a separate tablespace for every table and index a good idea?
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Optimizing the performance of the redo log buffer
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Write a SQL script with optional arguments
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Is there a table to define Oracle error messages?
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Cost factor in the explain plan and query execution time
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How do I copy an Oracle DB from one server to another?
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Advantages of reorganizing an Oracle database
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Different ways to back up a database
There are several ways to back up a database, including schema, table and full exports, as well as hot and cold backups. Here are descriptions of each method. Continue Reading
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Insufficient privileges to create views
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How to avoid resource busy error
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How to get the lengths of values in "long" datatype
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How to connect two databases to one listener
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Creating a backup of a table that contains a LONG type field
I need to take a backup of a selected number of rows from an Oracle table. I thought of doing a create table ... as select from. However, the source table consists of a LONG type field. How can I back this up? Can I use export? Continue Reading
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Retrieving all data from one table and putting it into another table
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How can I store and retrieve movie files in Oracle?
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Setting up notifications of OEM job status
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ORA-01113 and ORA-01110 errors on restarting database
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Updating data in remote database when local database is updated
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"ORA-12571:TNS:packet writer failure" error
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"ORA-12541: TNS:no listener" error
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"ORA-1652:unable to extend temp segment by 128 in tablespace TEMP" error
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Solutions for "ORA-12571: TNS Packet writer failure"
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Problems using backup control file
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dbms_output.put_line command is not working
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Using the ON DELETE CASCADE in Oracle
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Best way to update column of table with 5 million records
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Problem getting disconnected from server after one hour
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Loading CSV file to an Oracle table
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ORA-01002: fetch out of sequence error
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Using Java to find value of nextval
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Problems deleting 600,000 rows from partitioned table
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Converting COBOL style code to PL/SQL
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ORA-01840 error generated when running query
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What does SQL stand for?
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ORA-00959 error on trying to drop a tablespace
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Setting the timeout in listener.ora