ethiclab/dbffile

Read and write dBase III .dbf files in Node.js

DBFFile (Forked from https://github.com/yortus/DBFFile)

Reasons of the fork

This fork is an attempt to add support for:

1. dBase IV 0x8B file format. (EXPERIMENTAL)

Pre-requisites

1. yarn
2. typescript

Build

1. yarn run build
2. yarn test
3. yarn run prepublish

Summary

Read and write .dbf (dBase III) files in Node.js:

• Supported field types:
  • C (string)
  • N (numeric)
  • F (float)
  • I (integer)
  • L (logical)
  • D (date)
  • M (memo) Note: memo support is experimental/partial, with the following limitations:
    • read-only (can't create/write DBF files with memo fields)
    • dBase III file version 0x83 only
• Can open an existing .dbf file
  • Can access all field descriptors
  • Can access total record count
  • Can read records in arbitrary-sized batches
  • Supports very large files
• Can create a new .dbf file
  • Can use field descriptors from a user-specified object of from another instance
• Can append records to an existing .dbf file
  • Supports very large files
• Can specify character encodings either per-file or per-field.
  • the default encoding is 'ISO-8859-1' (also known as latin 1)
  • example per-file encoding: DBFFile.open(<path>, {encoding: 'EUC-JP'})
  • example per-field encoding: DBFFile.open(<path>, {encoding: {default: 'latin1', FIELD_XYZ: 'EUC-JP'}})
  • supported encodings are listed here.
• All operations are asynchronous and return a promise

Installation

npm install dbffile or yarn add dbffile

Example: reading a .dbf file

import {DBFFile} from 'dbffile';

async function testRead() {
    let dbf = await DBFFile.open('<full path to .dbf file>');
    console.log(`DBF file contains ${dbf.recordCount} records.`);
    console.log(`Field names: ${dbf.fields.map(f => f.name).join(', ')}`);
    let records = await dbf.readRecords(100);
    for (let record of records) console.log(records);
}

Example: writing a .dbf file

import {DBFFile} from 'dbffile';

async function testWrite() {
    let fieldDescriptors = [
        { name: 'fname', type: 'C', size: 255 },
        { name: 'lname', type: 'C', size: 255 }
    ];

    let records = [
        { fname: 'Joe', lname: 'Bloggs' },
        { fname: 'Mary', lname: 'Smith' }
    ];

    let dbf = await DBFFile.create('<full path to .dbf file>', fieldDescriptors);
    console.log('DBF file created.');
    await dbf.appendRecords(records);
    console.log(`${records.length} records added.`);
}

API

The module exports the DBFFile class, which has the following shape:

/** Represents a DBF file. */
class DBFFile {

    /** Opens an existing DBF file. */
    static open(path: string, options?: Options): Promise<DBFFile>;

    /** Creates a new DBF file with no records. */
    static create(path: string, fields: FieldDescriptor[], options?: Options): Promise<DBFFile>;

    /** Full path to the DBF file. */
    path: string;

    /** Total number of records in the DBF file (NB: includes deleted records). */
    recordCount: number;

    /** Metadata for all fields defined in the DBF file. */
    fields: FieldDescriptor[];

    /** Reads a subset of records from this DBF file. The current read position is remembered between calls. */
    readRecords(maxCount?: number): Promise<object[]>;

    /** Appends the specified records to this DBF file. */
    appendRecords(records: object[]): Promise<DBFFile>;
}


/** Metadata describing a single field in a DBF file. */
export interface FieldDescriptor {

    /** The name of the field. Must be no longer than 10 characters. */
    name: string;

    /**
     * The single-letter code for the field type.
     * C=string, N=numeric, F=float, I=integer, L=logical, D=date, M=memo.
     */
    type: 'C' | 'N' | 'F' | 'L' | 'D' | 'I' | 'M';

    /** The size of the field in bytes. */
    size: number;

    /** The number of decimal places. Optional; only used for some field types. */
    decimalPlaces?: number;
}


/** Options that may be passed to `DBFFile.open` and `DBFFile.create`. */
interface Options {

    /** The character encoding(s) to use when reading/writing the DBF file. */
    encoding?: string | {default: string, [fieldName: string]: string};
}