The control file is a text file written in a language that SQL*Loader understands. The control file tells SQL*Loader where to find the data, how to parse and interpret the data, where to insert the data, and more.
In general, the control file has three main sections, in the following order:
Session-wide information
Table and field-list information
Input data (optional section)
Some control file syntax considerations to keep in mind are:
The syntax is free-format (statements can extend over multiple lines).
The syntax is case-insensitive; however, strings enclosed in single or double quotation marks are taken literally, including case.
In control file syntax, comments extend from the two hyphens (--) that mark the beginning of the comment to the end of the line. The optional third section of the control file is interpreted as data rather than as control file syntax; consequently, comments in this section are not supported.
The keywords CONSTANT and ZONE have special meaning to SQL*Loader and are therefore reserved. To avoid potential conflicts, Oracle recommends that you do not use either CONSTANT or ZONE as a name for any tables or columns.
SQL*Loader Control File Reference for details about control file syntax and semantics