The database is a table of numbers, e.g., current, temperature, and density at a particular time in the discharge vs shot number. These parameters and their values are stored in a file which has the same name as your database and a DBC type. It may optionally contain a table of expressions and their names which is stored in the same file as your parameters. The database may also have a table of parameter and expression descriptions. The descriptions are stored in a different file which has the same name as your parameter file but with a DSC type.
Each parameter value can be up to 12 characters and can represent either a real number which can be plotted or just a string of characters that can be printed. NODATA is the missing data code. Note: values that cannot be converted to numbers, except for NODATA, cannot be used to specify constraints. See section 2.2 which describes constraints.
An expression can contain parameters of the database or an expression that precedes the one you are now defining. These expressions are treated as parameters in most of the LOCUS programs.
A parameter or expression description has three fields: a short description, units, and a long description. You can also have a database description or comment.