init.ora spfile both are contains Database parameters info. Both are supported by oracle. Every database instance required either any one. If both are present first choice is given to spfile only. (becareful if both are present any changes made in pfile those are not recongnized in next instance because it always first preference is givent to spfile only).

init.ora saved in the format of ASCII

SPFILE saved in the format of binary.

init.ora info is read by oracle engine at the time of database instance starting time only any modification made in this those are applicatble when in the next startup only. But in spfile modifications (through alter system..... command) can applicable without restarting oracle database(restarting instance).

spfile we can create with the help of

create spfile from pfile.

as well as we can create pfile (init.ora) from spfile

create pfile from spfile.

in general 24x7 environment spfile is only preferable because parameters can change dynamically.

any queries regarding this explanation pls. give some reply.

spfile are dynamic file.spfile can be created from pfile.you can open your database without spfile. init.ora is must to open the database.you can edit the init.ora file because it is a text file.whereas spfile cannot it reside on serverside.

init.ora as name suggested a initialisation file it is a simple text file oracle reads init.ora and according to init.ora oracle allocates memory of db_block_size and buffer cache and some other initallisation parameter it is having a diffrent name as operating system changes.

spfile is a binary file ... we cannot be changed

where as pfile is init file to start an oracle instance which allocates the memory resources for the database....

we can edit the pfile but we cannot do changes in spfile we can create

spfile from pfile..

SPfile is a binary file and init.ora file is a text file We can edit the init.ora file but we can't edit the spfile we can create spfile through init.ora file.

The use of spfile is--> we can directly startup the database otherwise if we don't have spfile for every startup of database we have to write the path of init.ora file

Thanks