Index (B-tree)

B-tree Index B-tree stands for Balanced Tree in RDBMS. It is commonly used in database and filesystem.The B-tree enables the database to find a leaf node quickly. It is a good example of a data structure for external memory. Telephone directory, library are the best example of B-tree index.   Why do we use B-tree? keeps keys in […]

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Oracle Database 12c Release 2 (12.2) Installation On Redhat Linux 6

In this post, I’m installing the Oracle Database 12c Release 2 ( software on Oracle Linux 6.4.  Only the software is being installed at this point, in preparation for a single database installation which I’ll create later on using the DBCA tool. First and foremost, before you start, make sure your Linux server meets the minimum […]

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Long Identifiers In Oracle 12.2

SQL*Plus now supports object lengths of 128 bytes. In previous releases, the object length limit was 30 bytes and if you try to create object with length more than 30, it will throw error as ORA-00972: identifier is too long. Oracle 12.2 increases the maximum size of most identifiers from 30 to 128 bytes, which […]

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spool CSV in Oracle 12.2

Now we can spool spool CSV or JSON from Oracle Database. Prior to 12.2 , we can spool as text or html, but from 12.2 onward, the SET MARKUP command now has a CSV option to output data in CSV format. Syntax CSV {ON|OFF} [DELIMI[TER] character] [QUOTE {ON|OFF}] Traditionally you wiill get formatted output (without […]

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Display the columns related to redaction in Oracle 12c

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How to make a table read only in Oracle

Oracle 11g allows tables to be marked as read-only using the ALTER TABLE command.

Let’s create a table and make it read-only.

Any DML statements that affect the table data results in an ORA-12081 error message.

DML and DDL operations return to normal once the table is switched back to read-write mode. […]

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