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Version: 3.6.X

General Structure of an ABCD Database

An ABCD database is not a single file, but a complex collection of folders and files that manage data, configurations, and interface rules for different modules.

Below is the detailed breakdown of the folders and files that constitute a complete ABCD database.

Directory Structure Overview​

Each database resides in a subfolder within the bases directory of your ABCD installation. For a database, the folder structure is as follows:

  • ayudas/: Local of field-level help files for data entry.
  • cnv/: Contains conversion files (.cnv) responsible for converting external files (like CSV) into the database structure.
  • data/: The actual data storage, the database itself.
  • def/: Directory with Field Definition Tables (FDT), worksheets (FMT), validation files (.val), and auxiliary tables (.tab).
  • loans/: Specific configuration and display rules for the circulation/loans module.
  • opac/: Configuration and structure specific to the public search interface.
  • pfts/: Print formats, advanced search forms, and statistics definitions.

1. ayudas (Field Help)​

This folder contains HTML files that provide contextual help for each field during data entry.

  • Help pages are typically named after the field tag (e.g., tag_001.html).
  • These are linked in the Field Definition Table (FDT) to assist catalogers during the input process.

2. cnv (Conversions)​

Contains .cnv files used for data transformation and migration.

  • These files define the rules for converting external formats (like CSV or MARC ISO) into the internal ABCD database structure.

3. data (Core Data Storage)​

This is the heart of the database where the actual information and its indexes are stored. Key file extensions include:

  • .mst (Master File): Contains the actual variable-length records.
  • .xrf (Cross-Reference File): Acts as a primary index, keeping track of the position of each record (MFN) in the .mst file.
  • .n01 / .n02 / .l01 / .l02 (Inverted File): These files form the B-Tree index (Dictionary) for fast searching.
  • .cnt (Control File): Manages the status and integrity of the inverted file.
  • .ifp: The main inverted file index.
  • .prc: Format for procedures and data processing.
  • control_number.cn: A file used by the auto-increment mechanism to assign unique identifiers.

4. def (Definitions)​

This directory stores the structural definitions of the database, often organized into language-specific subfolders (e.g., def/en, def/pt).

  • .fdt (Field Definition Table): Defines tags, names, types (repeatable, subfields), and basic behavior.
  • .fmt (Worksheets): Defines the layout and sequence of fields presented during cataloging.
  • .val (Validation): Contains rules to ensure data quality and mandatory field completion.
  • .tab (Tables): Auxiliary text files used for picklists or code conversions.

5. loans (Circulation Configuration)​

Since every database has its own field structure (different tags for title, control number, etc.), the Loans module requires specific mappings.

  • It defines which fields are used for identification and display within the circulation module.
  • Contains specific PFTs to show item status during loan transactions.

6. opac (Public Access Configuration)​

Following the same logic as the loans folder, each database requires a specific configuration for the OPAC.

  • It defines how the public search will behave for this specific database.
  • Maps the internal indexes to the search interface filters and facets.

7. pfts (Print Formats & Search Forms)​

Contains the ISIS Formatting Language scripts (.pft) that define record visualization.

  • Display Formats: Rules to generate HTML or text from database fields.
  • camposbusqueda.tab: Defines the structure of the internal advanced search form.
  • Statistics: Statistical configurations and definitions for reporting are typically managed within the PFT structures.

Visual Representation of the Structure​

A simplified view of the hierarchy looks like this:

bases/
└── database/
    ├── ayudas/ (tag_xxx.html)
    ├── cnv/    (.cnv)
    ├── data/   (.mst, .xrf, .cnt, .ifp, .fst)
    ├── def/    (.fdt, .fmt, .val, .tab)
    ├── loans/  (mapping pfts)
    ├── opac/   (interface config)
    └── pfts/   (.pft scripts)