Product Documentation

FairCom ISAM for C

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Data and Index Definitions

FairCom Server stores data in files. Two main types of files are discussed in this section:

  • Data files, which store the data found in database tables.
  • Index files, which provide rapid access to the data by storing an index to the data.

This section also discusses different file formats, file modes, and other details.

File Formats

FairCom DB (in releases V7 and later) supports two different, but related, file formats:

  • Standard file format - The default format for all versions of c-tree Plus and FairCom DB.
  • Extended file format - A format containing an extended header, which supports additional features, such as Huge and segmented file support. See Extended Feature Support.

The extended 8-byte file creation routines (e.g., CreateDataFileXtd8(), CreateIFileXtd8(), etc.) create Extended files by default. Extended files are not compatible with c-tree Plus V6. However, the extended 8-byte file creation functions will create Standard files when using the ctNO_XHDRS extended file mode. The existing file creation functions (e.g., CreateDataFile(), CreateIFileXtd(), etc.) create only Standard files.

The FairCom Drivers read both Standard and Extended files and create Standard files.

In This Section

Data and Index File Numbering

File Modes

Extended File Creation Block Structure

Extended Feature Support

Data File Extension