Secondary index

Hi, Does anyone know the advantages and disadvantages of having an secondary index ? What if it is for an update ? Or delete ? Thanks

Raghava Ponnapalli wrote: > > Hi, > > Does anyone know the advantages and disadvantages of having an secondary > index ? What if it is for an update ? Or delete ? Secondary indexes, or attribute indexes, are used to select data from a table based on the values of attribute columns that are not key. For example an employee database. If you are in HR and responsible to organize car pools for employees to comply with local government requirements to reduce traffic to and from your facility it would be nice to be able to search the employee table by zip code or city or even street name, etc. While relational database will permit you to do this without an index if you perform this type of search often it will save much time to index these columns. If you are making the inquiry in response to a phone call from an employee looking for a new car pool a faster query will get both of you back to doing 'real' work that much faster and save the company money. Art S. Kagel