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The FairCom DB API API automatically, and transparently, handles the details of fixed and variable-length records. A table is set to variable-length if it has at least one variable-length field. A fixed-length field always consumes the same amount of disk space in a table file, regardless of what is actually stored in that field. A variable-length field, on the other hand, consumes an amount of disk space that varies with the field's contents.
Variable-length fields require more housekeeping than fixed-length fields. Fortunately, FairCom DB API does this for you. FairCom DB API scans the user field definitions until it encounters the first variable-length field. If a table contains no variable-length fields, the record is set to fixed-length.
FairCom DB API also automatically calculates the size of the fixed portion of a record by adding the size of the fixed-length fields, taking into consideration the field alignment in the record buffer, until the first variable-length field is encountered. The variable-length fields are listed below, with the matching FairCom DB ISAM data type in parentheses:
CT_PSTRING (CT_PSTRING)
CT_VARBINARY (CT_2STRING)
CT_LVB (CT_4STRING)
CT_VARCHAR or CT_LVC (CT_STRING)
Any type of field can be placed anywhere in the record buffer and also be used as an index segment. FairCom DB API makes full use of this feature by providing the user with an advanced dynamic record buffer management.
