ODBC to Parquet

A command line tool to query an ODBC data source and write the result into a parquet file.

• Small memory footprint. Only holds one batch at a time in memory.
• Fast. Makes efficient use of ODBC bulk reads, to lower IO overhead.
• Flexible. Query any ODBC data source you have a driver for. MySQL, MS SQL, Excel, ...

Mapping of types

The tool queries the ODBC Data source for type information and maps it to parquet type as such:

| ODBC SQL Type | Parquet Logical Type | |-----------------------|------------------------| | Decimal(p, s) | Decimal(p,s) | | Numeric(p, s) | Decimal(p,s) | | Bit | Boolean | | Double | Double | | Real | Float | | Float | Float | | Tiny Integer | Int8 | | Small Integer | Int16 | | Integer | Int32 | | Big Int | Int64 | | Date | Date | | Timestamp(p: 0..3) | Timestamp Milliseconds | | Timestamp(p >= 4) | Timestamp Microseconds | | All others | Utf8 Byte Array |

p is short for precision. s is short for scale. Intervals are inclusive.

Installation

Download binary from GitHub

https://github.com/pacman82/odbc2parquet/releases/latest

Note: Download the 32 Bit version if you want to connect to data sources using 32 Bit drivers and download the 64 Bit version if you want to connect via 64 Bit drivers. It won't work vice versa.

Via Cargo

If you have a rust tool chain installed, you can install this tool via cargo.

shell script cargo install odbc2parquet

You can install cargo from here https://rustup.rs/.

Usage

Query using connection string

bash odbc2parquet query \ --connection-string "Driver={ODBC Driver 17 for SQL Server};Server=localhost;UID=SA;PWD=<YourStrong@Passw0rd>;" \ out.par \ "SELECT * FROM Birthdays"

Query using data source name

bash odbc2parquet query \ --dsn my_db \ --password "<YourStrong@Passw0rd>" \ --user "SA" \ out.par1 \ "SELECT * FROM Birthdays"

List available ODBC drivers

bash odbc2parquet list-drivers

List available ODBC data sources

bash odbc2parquet list-data-sources

Use parameters in query

shell odbc2parquet query \ --connection-string "Driver={ODBC Driver 17 for SQL Server};Server=localhost;UID=SA;PWD=<YourStrong@Passw0rd>;" \ out.par \ "SELECT * FROM Birthdays WHERE year > ? and year < ?" \ 1990 2010

Use odbc2parquet --help to see all option.

Links

Thanks to @samaguire there is a script for Powershell users which helps you to download a bunch of tables to a folder: https://github.com/samaguire/odbc2parquet-PSscripts