csv2db command line tool
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Java Runtime

How to Build

git clone https://github.com/anjlab/csv2db.git csv2db

cd csv2db

chmod +x gradlew

./gradlew build

How to Use

./build/libs/run.sh --help

usage: ./run.sh
 -b,--batchSize <arg>         Override batch size
 -c,--config <arg>            Configuration file
 -d,--driverClass <arg>       JDBC driver class name
 -g,--progress                Display progress
 -h,--help                    Prints this help
 -i,--input <arg>             Input CSV file, or ZIP containing CSV files,
                              or path to folder that contains CSV files
 -l,--connectionUrl <arg>     JDBC connection URL
 -m,--mode <arg>              Operation mode (INSERT, MERGE, INSERTONLY)
 -n,--include <arg>           Only process files whose names match this
                              regexp (matches all files in input ZIP or
                              input folder by default)
 -p,--password <arg>          Connection password
 -s,--skip <arg>              Skip files whose names match this regexp
                              (skip nothing by default)
 -t,--numberOfThreads <arg>   Number of threads (default is number of
                              processors available to JVM)
 -u,--username <arg>          Connection username
 -v,--verbose                 Verbose output, useful for debugging
 -V,--verbose2                Print some internal statistics every 1 minute

Command line options take precedence over values from config file.

run.sh supports $JAVA_OPTS environment variable.

Pick right database driver

This distribution shipped with latest PostgreSQL 9.x JDBC driver.

If you need to connect to different RDBMS try either:

  • (re)build csv2db with -PjdbcDriver=<groupId:artifactId:version> key.

    For example, to get latest 5.x MySQL Connector/J driver run build with:

    ./gradlew -PjdbcDriver=mysql:mysql-connector-java:5+ build
  • or manually put JDBC driver to ./build/libs/lib.

You can find names of JDBC drivers in Maven Central.


CSV file

Only few columns listed here, just to show the format of CSV that were used with config below.

CompanyName, CompanyNumber,RegAddress.CareOf,RegAddress.POBox,RegAddress.AddressLine1, RegAddress.AddressLine2
"! LTD","08209948","","","METROHOUSE 57 PEPPER ROAD","HUNSLET"

Config file

    "extend": "parent-config.json",
    "operationMode": "MERGE",
    "driverClass": "org.apache.derby.jdbc.EmbeddedDriver",
    "connectionUrl": "jdbc:derby:memory:myDB;create=true",
    "connectionProperties": {
        "username": { "function": "connectionUsername" },
        "password": ""
    "targetTable": "companies",
    "primaryKeys": [
    "columnMappings": {
        "0": "name",
        "1": "companies_house_id",
        "2": "address_care_of",
        "4": "address_line_1",
        "5": "address_line_2",
        "6": "post_town",
        "9": "post_code"
    "transientColumns": [
    "syntheticColumns": [
    "insertValues": {
        "id": { "sql": "nextval('company_id_sequence')" },
        "created_at": { "sql": "current_timestamp" }
    "updateValues": {
        "updated_at": { "sql": "current_timestamp" }
    "transform": {
        "post_code": { "function": "uppercase" },
        "address_line_2" : { "function": "transformAddressLine2" }
    "map": {
        "function": "filterRows"
    "scripting": [
    "forceUpdate": false,
    "batchSize": 100,
    "csvOptions": {
        "separatorChar": ",",
        "quoteChar": "\"",
        "escapeChar": "\b",
        "skipLines": 1,
        "strictQuotes": false,
        "ignoreLeadingWhiteSpace": true


Since version 2.2.0 csv2db will use Nashorn JavaScript engine (built-in to Java 8+) and fallback to Rhino if running on Java 7 and below. There's no switch to control this behavior.

Note: Nashorn is not a drop-in replacement for Rhino, so some things may stop working.

Follow this guide to upgrade your scripts from Rhino to Nashorn.

"use strict";

//load compatibility script when on Java 8



//  Map function accepts two arguments:
//  - `row` from CSV file containing only values according to `columnMappings`
//  - `emit` is a callback function that accepts new value of `row` that will
//    be used instead of original value
function filterRows(row, emit) {
    if (row.get("companies_house_id")) {

//  For functions used in connection properties
//  first argument is the name of evaluating connection property
function connectionUsername(propertyName) {
    return java.lang.System.getProperty("user.name")

function transformAddressLine2(columnName, row) {
    //  row.get("address_care_of") available here
    return StringUtils.trimToNull(row.get(columnName));

function uppercase(columnName, row) {
    return row.get(columnName).toUpperCase()

Format of config file

As shown in example above, config file should be in JSON format.

extend allows extending this config definition from parent config. For example, you may extract some common bits from your configs to one shared common file and extend from it. All paths in parent config will be relative to this configuration.

operationMode may be one of MERGE, INSERT or INSERTONLY.

In MERGE mode the data will be merged to the target table. This mode requires that the primaryKeys property is set. The tool uses primaryKeys to find the data in target database table for each CSV row data. Query by primaryKeys should return exactly 0 or 1 records. If 0 records will be found, then CVS row will be INSERTed to the database, otherwise an UPDATE will be performed and data from CSV will overwrite existing database record.

In INSERTONLY mode, it operates in a similar way to MERGE however the row will be ignored if the Query by primaryKeys returns a row. The effect is that only the rows that don't already exist in the database will be INSERTed in to the table.

driverClass, connectionUrl and connectionProperties are corresponding values from JDBC documentation for your database. Since version 2.1 it is possible to use JavaScript function references for connection properties.

targetTable is the name of target table in database. The table should exist before import.

primaryKeys is the set of primary keys on the table. Only used in MERGE and INSERTONLY modes. All primaryKeys should be present in columnMappings section, which means that CSV should contain primaryKeys data.

columnMappings defines mapping between zero-based column indexes in CSV and target database table column names.

syntheticColumns lists additional columns that need to be mapped to database columns. These additional columns can appear in rows as a result of map function (see below).

transientColumns defines mapped columns as transient, which means they are only available for JavaScript functions in the row argument, but these columns won't be mapped to target table columns.

insertValues and updateValues allows providing values for columns that are not in CSV (like in example above with required id field, whose value should be taken from PostgreSQL sequence). insertValues used in INSERT clauses, updateValues used in UPDATE clauses. See Value Definitions.

transform defines transformation rules for imported data. Right now you can define only one transformation for each column. See Value Definitions. Transformations only applied for CSV data and not for the columns defined in insertValues and updateValues

map (optional) defines name of a JavaScript function. Every row from input CSV file will be passed through this function. The map function must accept two arguments: row and emit. The value of row will be JSON object containing key/values according to columnMappings. emit is a callback function that accepts new value of row that will be used instead of original value in further processing. Client code may invoke emit function 0, 1, or many times, acting like a filter or a splitter.

scripting defines list of JavaScript file names. The file names are relative to location of the configuration file. You can define your JavaScript functions in these files and reference them from Value Definitions.

forceUpdate forces executing UPDATE statements for every row even if the data from CSV for this row is the same as in the database table. This may be needed if you want to force applying values from updateValues section. Default value is false and it is only used in MERGE mode.

ignoreNullPK ignores any row where any of the PK values in the data are null. This may be needed if you want to top up a reference table from a data table with missing reference values where some of them are null. Default value is false and it is only used in INSERTONLY mode.

ignoreDuplicatePK ignore rows having exactly the same values of PK when they appear in the same insert batch (see batchSize). Only first record from the batch will be used for insertion.

batchSize size of INSERT/UPDATE batches. Default value is 100.

csvOptions is a set of options supported by http://opencsv.sourceforge.net, here's the defaults:

    "separatorChar": ",",
    "quoteChar": "\"",
    "escapeChar": "\\",
    "skipLines": 0,
    "strictQuotes": false,
    "ignoreLeadingWhiteSpace": true

Value Definitions

Value definitions used to define column values in the insertValues, updateValues and transform blocks.

Value definition may be one of:

  • Constant
  • SQL expression
  • JavaScript function reference

Constant value definitions are JSON primitives, and can be strings, numbers or booleans. Use this when you want the same value for all rows of the column:

    "insertValues": {
        "data_source": "CompaniesHouse",
        "official_data": true
SQL expression

Result of SQL expression value definition becomes a part of SQL query, in contrast to "Constants" and "JavaScript function references" whose values becomes SQL query parameters.

    "insertValues": {
        "id": { "sql": "nextval('company_id_sequence')" }

SQL expressions are only allowed to be used for insertValues and updateValues. This is due to performance issues, because INSERT and UPDATE clauses prepared only once and then reused for import of every row.

JavaScript function reference

You can reference one of the functions that declared in JavaScript files from scripting block:

    "transform": {
        "post_code": { "function": "uppercase" }

Every function will accept two arguments:

  • columnName -- name of the column for which this function should produce a value, and
  • row -- JSON object representing key-value pairs of currently imported CSV row. Only columns that are in columnMappings will be present in this object.

If the function referenced from context of insertValues or updateValues then row argument will be null. Note that primary key values will be transformed before being checked against the primary key in both MERGE and INSERTONLY modes, enabling transformation of primary key values.