Ask the Experts
Ask the Experts
Oracle database administration
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Calling stored procedures inside user-defined functions in Oracle Database
In this expert answer, Brian Peasland explains how to call a stored procedure inside user-defined functions in Oracle Database. Continue Reading
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Copy Oracle Database but with no data
One reader asks how he can make a copy of his Oracle Database but not have any data in it, for test purposes. Continue Reading
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How to add disk to ASM diskgroup with two-way mirroring
Learn how to add disk to ASM diskgroup with two-way mirroring and how to specify a failgroup in this tip from Oracle expert Brian Peasland. Continue Reading
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How to decrypt an Oracle password using John the Ripper and checkpwd
Learn how to decrypt an Oracle password with Oracle password crackers like John the Ripper and checkpwd in this tip from an Oracle security expert. Continue Reading
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How to use the CREATE SESSION command to track Oracle database logins
Oracle security expert Brian Peasland explains how to use the CREATE SESSION command in an Oracle audit table to track Oracle user database logins. Continue Reading
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Can I download DBCA for Oracle Express Edition?
Understand how to install the DBCA in Oracle 10g Express Edition and why you cannot simply download DBCA in Oracle in this expert tip. Continue Reading
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Can I create multiple schemas in Oracle for one user?
Want to create multiple schemas for one user in Oracle? Learn whether it's possible here. Continue Reading
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How to solve an ORA-1555 error in the Oracle testing database
Expert Brian Peasland explains to a SearchOracle.com reader asks why the ORA-1555 error is showing in the Oracle testing database but not in production Continue Reading
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How to disable Oracle constraints and triggers during an import in 10g
An Oracle user asks expert Brian Peasland if constraints and triggers can be disabled on an Oracle import in Oracle 10g and how to complete this task. Continue Reading
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Why am I receiving the ORA-12535 error when using a remote database?
An Oracle user asks why they are receiving the error ORA-12535: TNS: operation timed out when using a remote database. Continue Reading
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Defining RTO, MTBF and MTTR
Database backup and recovery expert Brian Peasland explains the terms RTO, MTBF and MTTR. Continue Reading
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What is the difference between an instance and mounting in Oracle?
An Oracle user asks what the difference is between an instance and mounting. Continue Reading
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Import on one table from dump file
An Oracle user asks if it is possible to do an import on one table from a large dump file. Continue Reading
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How to drop tablespace with missing datafile
Oracle expert Brian Peasland explains how to drop a tablespace with a missing datafile and recreate the tablespace. Continue Reading
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What is the difference between obsolete and expired status?
Oracle expert Brian Peasland explains the difference between obsolete status and expired status. Continue Reading
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LOB tables missing with exp/imp move of schema
I have a problem when moving a schema using exp/imp. After import, the tables with LOBs are missing. Continue Reading
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Add or drop inactive online redo log files
Can we add or drop (inactive) online redo log files at the open stage? Continue Reading
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Query on dblink returning ORA-12545 error
I have a dblink between Oracle 9i and Oracle 10g. When I execute this query sometimes I get the result, but sometimes I get the error "ORA-12545." Continue Reading
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Restore database from backup without control files
If you just had to restore from backup and do not have any control files, how would you go about bringing up this database? Continue Reading
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How to create an index using a procedure in Oracle
How can we create an index using a procedure? Continue Reading
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How to increase SGA_MAX_SIZE in Oracle
How to increase SGA_MAX_SIZE in Oracle? I got the error "ORA-03113: end-of-file on communication channel" during startup. Continue Reading
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When will support for Oracle 9i be discontinued?
When will general support for Oracle 9i be discontinued? Continue Reading
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What should my global database name be?
When I type hostname it returns me this localhost.localdomain. So what should be my global database name if SID is ora9i? Continue Reading
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Check current SCN in control file
How to check current SCN or header in the control file? Continue Reading
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Definitions of checkpoint, PMON and SMON
What is a checkpoint? What are PMON and SMON? Continue Reading
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Migrating database from Solaris to Linux
What is the procedure to migrate an Oracle database from a Solaris machine to Red Hat Linux 9? Continue Reading
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Invalid stored procedures
When running an application that is connected to an Oracle server/database and trying to add rows or make a call to the DB, I am getting various errors that the stored procedures are invalid. Continue Reading
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Non-zero values for SHARED_POOL_SIZE and JAVA_POOL_SIZE
I am getting an ORA-04031 error. I have a two-node 10g RAC cluster. If I gave both SHARED_POOL_SIZE and JAVA_POOL_SIZE values (thus overriding the defaults) how would this affect the running of the CLUSTER? Does a CLUSTER require these values to be ... Continue Reading
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Exporting selected procedures and functions in Oracle
How can we export selected procedures/functions/packages in Oracle? Continue Reading
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Consistent vs. inconsistent backup
What are consistent and inconsistent backups? Continue Reading
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Check if date is greater than 2000 in PL/SQL
How to check if the date is greater than the year 2000 in PL/SQL? Continue Reading
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Standard vs. Enterprise Editions of Oracle
What's the difference between Standard Edition and Enterprise Edition? Continue Reading
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Easy way to import public synonyms?
Using export/import to update a development database, I normally do a schema (user) import. Is there an easy way to import public synonyms? Continue Reading
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Converting a column from VARCHAR2 to DATE
I need to convert a date column created using data type VARCHAR2 into data type DATE. Is it possible? 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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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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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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How do I copy an Oracle DB from one server to another?
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Purpose of roll forward and roll backward
What are rolling forward and rolling backward in backup and recovery? Continue Reading
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ORA-12801 and ORA-01652 errors on running query
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Telling EXECUTE IMMEDIATE to commit
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DIRECT=Y versus DIRECT=N when importing
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Inserting the '&' symbol in a string
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Checking if row is locked before using it in a procedure