1. why the performance of the table is degraded when more index is created on the table......2. whats the main usage of synonym other than that of creating other names to objects....3. shall we able to create an primary index on the table which already has the null value? if yes syntax please.........4. whats the main usage of trigger.......... (eg..) please...

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ks keerthi

  • Apr 28th, 2006
 

too many index-a problem as if too many index are created oracle engine takes longer to insert a record in table as index processing must be done after every record. thanks, keerthi.

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Sushma

  • Jul 11th, 2007
 

3.If we have the null values in the column then we can not create primary key trigger on that column.

4. It is an event that raised implicitly when you update the table.

Regards,
Sushma

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shravanam

  • Oct 28th, 2007
 

1. When you create more indexes on a table , for example  table A has 10 columns and you have create 8 indexes on that table. Then whenever you r going to retrieve data from that table each row of that column has to go the index address and get the data. so it will take a lot of time and it will degrade the performance of your table.

3. We cant create a primary key on a column thats having a null column. If you want to create a primary key, you have delete all the data in that column and then create a primary key on that one.


4. Triggers r used to perform a specific action whenever a triggering events take place just like insert, update,delete

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