This post covers over 200 commonly observed row source operations (, which is a unique combination of operation and options) with an example to reproduce the operation. A list of operations and options as of 11g R2 is available here, you should note that not all options are available for each operation. ALTER INDEX STATEMENT [...]
Archive of posts tagged Oracle8i
OVERLAPS predicate
OVERLAPS predicate is a useful feature, which is not available in most SQL implementations that can help to determine whether the two periods overlap each other. If two periods overlap then the predicate evaluates to TRUE otherwise FALSE. Let us create a test table with three rows – one with overlapping dates, second with non-overlapping [...]
Removing table rows using an inline view
The SQL standard allows you to use an inline view in a DELETE statement, see the pseudo form below – If a condition such as key-preserved table is not met then it will result in error, “ORA-01752: cannot delete from view without exactly one key-preserved table.” DELETE (SELECT some_column FROM table_one JOIN table_two USING (join_column)); [...]
How to create an Oracle User to use both OS Authentication and Password Authentication (REMOTE_OS_AUTHENT and OS_AUTHENT_PREFIX)
The initialization parameter REMOTE_OS_AUTHENT offers the trusted authentication model to the network, which is users can have OS accounts on machines other than the database server and gain access to database, convenience of single sign-on through remote OS authentication
OERR: The command line Oracle error code lookup utility
OERR stands for Oracle Error, which is a utility ships with Oracle distribution for Linux and UNIX that helps retrieve messages from message (.msg) files based on the supplied error code. This utility is not available for Windows, but there are variants freely available on the Internet.
Oracle Metadata: PLAN_TABLE
PLAN_TABLE is the default sample output table into which the EXPLAIN PLAN statement inserts rows describing execution plans. This post summarizes the metadata information of this table for Oracle8/8i, 9i, 10g, and 11g; read post, to know the methods for obtaining the formatted explain plan output from plan_table. STATEMENT_ID: VARCHAR2(30) – Value of the optional [...]
Oracle Statistics Package (STATSPACK): A Free Performance Analysis Tool
Statspack is a set of SQL, PL/SQL and SQL*Plus scripts which allow the collection, automation, storage and viewing of performance data. A user, PERFSTAT, is automatically created by the installation; owns all objects needed by this package. This user is granted limited query-only privileges on the V$views required for performance tuning. A Statspack report is generated from two snapshots, which is nothing but a collection of contents from various dynamic performance tables.
How to identify PL/SQL performance bottlenecks using DBMS_PROFILER
The DBMS_PROFILER package provides an interface to profile existing PL/SQL applications and identify performance bottlenecks. You can then collect and persistently store the PL/SQL profiler data.
How to run multiple Oracle database instances on a single server
You can have multiple instances on the same machine, each with their own data files, either sharing the ORACLE_HOME or each with different ORACLE_HOME. ORACLE_HOME and ORACLE_SID are the key environment variables used by Oracle to identify an instance. In addition $ORACLE_HOME/bin must be in your PATH environment variable. To check the value of these [...]
Tuning SQL statements with AUTOTRACE in SQL*Plus
You can automatically get a report on the execution path used by the SQL optimizer and the statement execution statistics. The report is generated after successful SQL DML (that is, SELECT, DELETE, UPDATE and INSERT) statements. It is useful for monitoring and tuning the performance of these statements. To use this feature, you must create a PLAN_TABLE table in your schema and then have the PLUSTRACE role granted to you. DBA privileges are required to grant the PLUSTRACE role.