Oracle imp and exp commands

Normally when i have to take a backup of of a database on unix, i do,

exp DBUSER/DBPSW@INST file=xxx.dmp

or load from a dump

imp DBUSER/DBPSW@INST file=xxx.dmp

my question here i开发者_运维技巧s :

1. how can we take a backup of a single table
2. how can we import the data backup from the dump into a single table.
3. how can we disable the constraints when taking a backup

I rarely do these when required.some times i need to do the above mentioned things but instead because i donot know i take the complete backup of all the table and load it. does anybody know how we can do it?

You can list tables you want to export or import in your command line as 'tables=...' Or run exp/imp interactively and it will ask you for list of tables. Here is a good FAQ