http://oracle-database-tips.com/wp News for Oracle professionals Sat, 27 Feb 2010 15:58:32 +0000 http://backend.userland.com/rss092 en Need to see how many unique ORA- errors your alert log contains ? cat alert_DBID.log | grep ORA- | sort | uniq That's all there is to it.. http://oracle-database-tips.com/wp/oracle-scripts/grep-unique-ora-errors-in-the-alertlog Oracle Database Hosting Comparison of companies offering Oracle web hosting This 'Oracle Database Hosting' article lists companies who specialize in hosting oracle databases. You will need to perform your own due diligence research into their ... http://oracle-database-tips.com/wp/oracle-hosting/oracle-database-hosting-companies Oracle Magazine Subscription The best way to keep up to date with Oracle's world is to subscribe to Oracle Magazine. Incredibly, it is still possible to subscribe to this informative magazine and have it delivered anywhere ... http://oracle-database-tips.com/wp/oracle-magazine/oracle-magazine Always test these 'troubleshoot oracle database link errors' commands on a test server before implementing them on a production server. There are a number of errors that you can face when working with database links in Oracle. Below are a list of some ... http://oracle-database-tips.com/wp/dblinks/troubleshoot-oracle-database-links Know your open links Once you have created and made use of a database link in Oracle, you might want to keep an eye on the number of concurrent open database links in your database so you can tune the open_links initialization parameter. Read more here on limiting concurrent open links. You will need to ... http://oracle-database-tips.com/wp/dblinks/manage-oracle-database-links Determine the maximum allowable number of database links per session in your database Each session in your database has a limited number of database links that can be opened at the same time. This number is determined by a database-wide initialization parameter: ... http://oracle-database-tips.com/wp/dblinks/limit-oracle-database-links-per-session Use a view or synonym to hide distributed database complexity from your user There are 2 ways you can hide the complexity involved with Oracle database links from your user: create a synonym or a view. This will allow your user to access the data ... http://oracle-database-tips.com/wp/dblinks/hide-oracle-database-link How to drop a database link Dropping a database link from your Oracle database is as easy as doing the following: drop database link remotedb; or drop public database link remotedb; You will need no other system privilege other than the 'create database ... http://oracle-database-tips.com/wp/dblinks/drop-oracle-database-link Once a database link has been created you are now ready to select your data from the remote database referenced by the db link. The syntax is : select <column list> from <table>@<dblink name>; For example: SQL> select * from dept@remotedb; DEPTNO DNAME ... http://oracle-database-tips.com/wp/dblinks/use-database-links Syntax : CREATE {PUBLIC} DATABASE LINK {CONNECT TO IDENTIFIED BY } USING ' '; Privileges needed When creating an oracle database link, you can decide to create it privately, for use only by the owner of the database link, or publicly, for use by all other database users who have the right privileges. If you do not ... http://oracle-database-tips.com/wp/dblinks/create-oracle-database-link A Database Link allows you to access data in a remote database as if it is a local table's data. The connection can be made to a database hosted on the same machine or ... http://oracle-database-tips.com/wp/dblinks/oracle-database-links-background This section, standby db tutorials aims to give you real-life examples and practical advice on setting up and maintaining Oracle's standby database technology, now called Oracle Data Guard. Standby databases are no longer very ... http://oracle-database-tips.com/wp/standby/standby-database-commands If you have ever sighed at needing to kill a number of Oracle processes related to one aspect of Oracle (listener,instance, agent, oms) then you will enjoy using this little script as much as I do now that I've found it. Be very careful with it, if you get the 'requirement' wrong, ... http://oracle-database-tips.com/wp/oracle-scripts/kill-oracle-processes-using-grep-only A cursor is a name used to access a specific private SQL area. Oracle creates implicit cursors for all SQL DML (data manipluation language) statements, even for select statements returning one row. If your query returns more than one row, you can explicitly ... http://oracle-database-tips.com/wp/oracle-scripts/open-cursors Your server is under pressure and you have decided to kill the oracle session which is causing excessive CPU or memory consumption, here's how you can find the oracle session associated with a unix process: Use top on the unix command line to see which process is the main culprit: (use shift+M to ... http://oracle-database-tips.com/wp/oracle-scripts/match-os-process-to-oracle-session Came across this very handy utility recently. Warning, it is unsupported by Oracle, so don't base your mission-critical alerts on this method. Let's say you are creating a stored proc as user scott, and instead of ... http://oracle-database-tips.com/wp/oracle-scripts/raise-alertlog-error There will be times when you want to compile a schema which does not belong to you, or for which you do not have the password. The solution is to use the dbms_utility package as a DBA user. Example, if you want to recompile ... http://oracle-database-tips.com/wp/oracle-scripts/compile-anothers-oracle-schema NFS Mount is incredibly useful in a corporate unix environment. You can use it to share disk space amongst servers, so that each server 'sees' the shared filesystem as if it is local. If your network is fast enough, you can backup your ... http://oracle-database-tips.com/wp/oracle-scripts/nfs-mount-article Below is an example script (check_stby.sql) which I've used to compare the most recently applied archive log file at a standby database to the most recently archived log at the primary database. (I know, DataGuard can do this for me with much less effort..) I am using sql*plus bind variables because I ... http://oracle-database-tips.com/wp/sqlplus/sqlplus-bindvariables If you can't find the sql script to drop the demo tables in your $ORACLE_HOME/sqlplus/demo folder (or %ORACLE_HOME%\sqlplus\demo on windows) you can cut it from this page and paste it in a text editor of your choice. Save it to a file on your server or PC and run it to complete dropping ... http://oracle-database-tips.com/wp/sqlplus/demodropsql If you can't find the demobld.sql in your $ORACLE_HOME/sqlplus/demo folder (or %ORACLE_HOME%\sqlplus\demo on windows) you can cut it from this page and paste it in a text editor of your choice. Save it to a file on your server or PC and follow the instructions in the oracle sqlplus demo table article to complete building ... http://oracle-database-tips.com/wp/sqlplus/demobldsql Create scott and run the oracle sqlplus demo table creation script by following the instructions below. Scott is the standard example schema used to run queries and scripts to show how Oracle works. Scott schema creation. Create the scott user on your database if it does not already exist. Connect to the database as a ... http://oracle-database-tips.com/wp/sqlplus/sqlplus-demo-table-setup A foreign key is one of the different types of Oracle constraints. The purpose of a constraint is literally to constrain or restrict the quality of data which you are allowed to insert into a table. There are 5 kinds of constraints : Check http://oracle-database-tips.com/wp/sql/foreign-key-constraints-and-other-type-of-constraints-in-an-oracle-database Oracle functions are very handy utilities to help you massage a result set to conform to your requirements, whether you are selecting, inserting, deleting or updating. Below is a list of some commonly used sql functions, with an example of each: add_months avg ceil chr concat count decode dump floor greatest initcap instr last_day least length lower lpad ltrim max min mod months_between next_day nullif nvl nvl2 replace round rpad rtrim sqrt substr sum sysdate to_char to_date to_number translate trim trunc ... http://oracle-database-tips.com/wp/sql/oracle-functions Contents Definition Simple subquery Correlated subquery Update with correlated subquery Delete with correlated subquery Definition A subquery is basically a select clause which is used instead of another statement. For example : Have a look at the following 2 tables : DEPT and EMP SQL> select * from dept order by deptno; DEPTNO DNAME ... http://oracle-database-tips.com/wp/sql/oracle-subquery Always test these 'oracle delete' commands on a test server before implementing them on a production server. The Oracle Delete statement allows you to remove rows from a table. The syntax is : delete from (where ); If you specify the delete statement without the where clause, you will delete all rows from a table. Specifying ... http://oracle-database-tips.com/wp/sql/oracle-delete-syntax The Oracle update statement allows you to change the data inside a table. Syntax update set = where ; If you do not specify a where clause, all rows in the table will be updated. Permissions You must have update privileges to update another schema's table. If you want to update through a ... http://oracle-database-tips.com/wp/sql/oracle-update-syntax Examples and explanation The Oracle Insert statement allows you to add data to a table. Contents : Inserting without specifying column names Inserting by specifying column names Insert a column's default value Inserting a null value Inserting multiple rows by means of a subquery The syntax is : insert ... http://oracle-database-tips.com/wp/sql/oracle-insert How to query the Oracle database Always test these 'select' commands on a test server before implementing them on a production server. This tutorial will show you how to use the correct syntax to query data in the Oracle database. When you query an object, ... http://oracle-database-tips.com/wp/sql/oracle-sql-select SQL is short for Structured Query Language. It is the language you will use to access any data structure or its data in the Oracle database. You will use this to issue commands to send instructions to the database. It is a standard across all compliant databases. SQL commands work on sets of data ... http://oracle-database-tips.com/wp/sql/sql-background Finding Large Directories To find large directories, use the du command and sort the output. For example, to output the 10 largest directories in /var, sorted in ascending size order, use the following command: du -ko /var|sort -n | tail -10 To avoid crossing file system boundaries, that is, to see the directory usage ... http://oracle-database-tips.com/wp/oracle-scripts/solaris-how-to-find-large-files-and-directories Your listener.log file can get quite large if you do not make it part of your housekeeping scripts, and renaming it while the listener is running is not a good idea. Here is the method to follow to clean it up while your listener is still running. Log into your listener from ... http://oracle-database-tips.com/wp/oracle-scripts/get-rid-of-large-listenerlog-file-while-the-listener-is-still-running SQL> select DF.TOTAL/1048576 "DataFile Size Mb", 2  LOG.TOTAL/1048576 "Redo Log Size Mb", 3  CONTROL.TOTAL/1048576 "Control File Size Mb", 4  (DF.TOTAL + LOG.TOTAL + CONTROL.TOTAL)/1048576 "Total Size Mb" from dual, 5  (select sum(a.bytes) TOTAL from dba_data_files a) DF, 6  (select sum(b.bytes) TOTAL from v$log b) LOG, 7  (select sum((cffsz+1)*cfbsz) TOTAL from x$kcccf c) CONTROL; http://oracle-database-tips.com/wp/oracle-scripts/quick-sql-to-determine-your-database-size-excluding-tempfiles Kill a bunch of related orphan Oracle processes with one command. Permalink -- click for full blog postRelated BlogsRelated Blogs on kill oracle processRelated Blogs on oracle process http://oracle-database-tips.com/wp/oracle-scripts/kill-oracle-processes We've partnered with Insight24 to bring you great free technology-focused webcasts and videos. Permalink -- click for full blog postRelated BlogsRelated Blogs on technology webcasts http://oracle-database-tips.com/wp/technology-webcasts/free-technology-webcasts Quick tutorial to download, install and use Free VNC for Linux. This will give you 'remote desktop'-type functionality on UNix. Permalink -- click for full blog post http://oracle-database-tips.com/wp/oracle-scripts/vnc-tutorial Quick page to remind myself what options to use with the linux du command to summarize the list of directories, not all the files. Permalink -- click for full blog post http://oracle-database-tips.com/wp/oracle-scripts/linux-du-command-options-used-to-summarize-directory-space-usage Installing and running vsftpd on your CentOS 4.5 server Permalink -- click for full blog post http://oracle-database-tips.com/wp/oracle-scripts/vsftpd Use these steps to publish oracle awr reports regularly and mail them to yourself Permalink -- click for full blog post http://oracle-database-tips.com/wp/oracle-scripts/awr-reports Automate the transfer of files across servers with this oracle ftp script. Permalink -- click for full blog post http://oracle-database-tips.com/wp/oracle-scripts/oracle-ftp-script