What is sql Loader...in details

Question

What is sql Loader...in details...

Answer 1

It is one of Oracle's bulk data loading tools. You use it to load data from flat files (such as CSV) into the database.

For details, please check their documentation (or this FAQ)

Answer 2

SQL Loader is utility provided by Oracle which enables us to load data from flat files into database tables. It is well covered in the documentation (check the Utilities Guide). The key thing is that SQL Loader is an external OS program.

External tables were introduced in Oracle 9i, allowing us to define tables whose data is supplied from flat files. These provide most of the functionality of SQL Loader with a lot more convenience. For instance we can manipulate and re-format the data using SQL functions which is simpler than using SQL Loader's syntax. It also means that we can pull the data from inside the database rather than pushing it from the OS.

However, for loading huge volumes of data in ultra-quick time a well-tuned SQL Loader control file will beat external tables for performance. Also, if there is a complicated OS process associated with the data files - e.g. ftp, gunzip, pre-processing with sed or awk - it can be more convenient to call SQL Loader from inside the shell script rather than attempting to hook up with a database job. So SQL Loader is still useful in certain scenarios but it is not necessarily the automatic first choice.