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Many production oracle database instances do not have auto incrementing tablespaces. You would need to know beforehand before users start getting ORA-01688 unable to extend tablespace errors. You would probably have some sort of monitoring on the tablespaces already , OEM shows alerts about tablespaces readily as well. But its good to have a query handy to quickly check the tablespace usages you have in your system. select df.tablespace_name ,totalusedspace "totalusedspace_mb" , (df.totalspace - tu.totalusedspace) "Free_MB", df.totalspace "Total_MB", round(100 * ( (df.totalspace - tu.totalusedspace)/ df.totalspace)) "Pct. Free" from (select tablespace_name, round(sum(bytes) / 1048576) TotalSpace from dba_data_files group by tablespace_name) df, (select round(sum(bytes)/(1024*1024)) totalusedspace, tablespace_name from dba_segments group by tablespace_name) tu where df.tablespace_name = tu.tablespace_name ;

Oracle string quote escape tool : There will be a times when you are writing dynamic sql and that sql  has lot of quote constants in where clause or in your select list , escaping these quotes can be quite cumbersome if you don't have the right tool. If you have a large query or string which has quotes in it  and you do not want to bother checking the escapes and want to use the escaped query / string readily in your plsql. Below tool will help you generate escaped string from Oracle  plsql standpoint , just copy and paste it in your code It's not ours to take. Escape quotes

There are times when writing a code when we want to write files with Oracle utl_file package, but we do not have access to v$parameter tables or do not know if the directory object exists in Oracle or not. There are also many times cases when you are tracing error in multi hundres of lines of code and do not know if the file writing is causing error or its some other code in your plsql. One can quickly test file writing is happening or not with the help below small code. DECLARE ---------- Oracle utl file write test. L_HANDLER UTL_FILE.FILE_TYPE; BEGIN L_HANDLER := UTL_FILE.FOPEN ('/xfer/data', 'utl_test.txt', 'W'); UTL_FILE.PUTF (L_HANDLER, 'UTL_FILE Test Success'); UTL_FILE.FCLOSE (L_HANDLER); END;

This is a Beginner level article but can be referred readily by guys using Oracle Database moderately for a refernence. You can identify the duplicate records in Oracle Table by using a group by clause. You need to group by column / columns from which you are trying to identify the duplicates , use count() function to identify the duplicates : expression is self exploratory having count () > 1 . Ex 1 : Identify duplicates first names from employees table.  Note in this context : Employee records is not necessarily duplicate we are only trying to find employees with same first name. select empl_first_name , count(empl_first_name) from employees group by empl_first_name having count(empl_first_name) > 1 Ex 2 : Identify duplicates or repeats based on 2 or more columns. select empl_first_name , empl_last_name , count(empl_first_name) from employees group by empl_first_name , empl_last_name having count(1) > 1 Identify duplicate / repeats based on 2 or more c

We always find a need to use incremental sequence for our table data columns like primary key or other unique keys. Examples of such fields could be id fields like employee id or order sequences for order processing in OLTP databases. Oracle provides very efficient non blocking way of getting and generating these new sequences with a database object called sequence. Sequence should be created and used as follows. CREATE SEQUENCE employee_id_seq START WITH 10000 -- Start your sequence with 10000 INCREMENT BY 1 -- Sequence would be incremented by 1 when nextvalue is fetched from sequence NOCYCLE; -- Oracle sequence would not restart -- If you want sequence to start over after N then specify maxvalue N clause in the sequence Full syntax of sequence statement Once we are done creating sequence object in database next thing is pretty straightforward. You can use your sequence immediately in insert statement. INSERT INTO EM

 If we want to perform hierarchical queries we need to use connect by clause in our sql query. Hierarchical query is any query wherin you want to display parent child relationship with the case that a parent may have multiple children and those have their own creating a tree like structure. One classic scenario highlighted on almost all sites is employee table wherein employee's manager is stored in the employee row the manager id is again one of the employee in the employee table. But we are not going to take it as you can reference it almost on any site that hosts oracle based content. We are going to do a query based on DBA_DEPEDENCIES or ALL_DEPENDANCIES if you do not have access to former. In DBA_DEPENDANCY table we have hierarchy of REFERENCED_NAME(parent) and the referring objects in column NAME(child ) that have dependency on the parent. with this in mind we would need to set our connect by clause as prior NAME= REFERENCED_NAME This confirms that REF

In this tutorial video we have demonstrated how to use oracle analytical functions like lag , lead , sum and avg etc. Example 1. Use of oracle function sum to display running totals with the use of unbounded preceding. select sum(Salary) over (order by salary rows unbounded preceding) running_total , salary , e.* from employees e Identify gap in the contiguous sequences with the lag function. Ex. In Employees table we have contiguous sequence of employees but due to some anomaly we found that there is now gap in the sequences. Ex Employee Id 210 comes after 206 which is not contiguous. We can write a query as given below to identify such sequence gaps. Oracle Lag Function select * from ( select lag (e.employee_id , 1) over (order by e.employee_id) as prev_emp, e.* from employees e ) tmp where (tmp.employee_id - tmp.prev_emp) > 1

If you have 3000 lines of code and a custom exception handler like when others. The ORA 06502 can be  notoriously elusive to find. This error is caused by . Trying to assign a higher length/precision value to variable whose size / precision is smaller than the value being assigned. Or trying to assign a non numeric value to a numeric variable. Ex . This is easy to see in 5 line code but if you have 3000+ lines of code and you did not handle the exception correctly. (plenty of times we write a generic when others handler which does not give us the line number but only a petty error message which says Numeric or valuer error.)  This would be the case wherein you would need to debug or trace where the error is occurring. Here's how you can debug such failure in this case. 1. If you are on your development or test enviornment , strip off all your excption handler in your package , procedure , function whatever it is that's throwing this error. When you run