This is yet another attempt to create a good interface to PostgreSQL from the D 2.0 programming language.
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(Under development - undocumented functions should be used with care.)

This is yet another attempt to create a good interface to PostgreSQL from the D programming language.

It is doesn't add overhead to the original low level library libpq but make convenient use PostgreSQL from D.


  • Arguments list support
  • Binary and text data queries
  • Reading of the text query results to native D text types
  • Representation of the binary query results to native D types
  • Text types
  • Integer and decimal types (except "numeric")
  • Timestamp type (with and without timezone)
  • LISTEN/NOTIFY support


####Requirements: Currently code builds with libpq 9.1.0 and higher, compiler dmd 2.060 and GNU make.

git clone
cd dpq2

####Debug version (with debugging symbols and asserts) $ make debug

####Unittest version (see below) $ make unittest

####Release version $ make release


$ make


#!/usr/bin/env rdmd

import dpq2.answer;
import std.stdio: writeln;

void main()
    Connection conn = new Connection;
    conn.connString = "dbname=postgres";

    // Text query result
    auto s = conn.exec(
        "SELECT now() as current_time, 'abc'::text as field_name, "
        "123 as field_3, 456.78 as field_4"
    writeln( "1: ", s[0,3].str );

    // Binary query result
    static queryArg arg;
    queryParams p;
    p.resultFormat = dpq2.answer.valueFormat.BINARY;
    p.sqlCommand = "SELECT "
        "-1234.56789012345::double precision, "
        "'2012-10-04 11:00:21.227803+08'::timestamp with time zone, "
        "'first line\nsecond line'::text";

    auto r = conn.exec( p );    
    writeln( "2: ", r[0,0].as!PGdouble_precision );
    writeln( "3: ", r[0,1].as!PGtime_stamp.toSimpleString );
    writeln( "4: ", r[0,2].as!PGtext );

Compile and run:

$ dmd example.d -Ldpq2/libdpq2.a -L-lpq -L-lcom_err
$ ./example 
1: 456.78
2: -1234.57
3: 0013-Oct-05 03:00:21.227803Z
4: first line
second line

Unit tests

Code contains embedded unit tests using a regular functions calls, not using standard D unit tests. It is because unit tests need to receive parameters of connection to the database in runtime.

To perform unit test it is required access to any PostgreSQL server with permissions to run SELECT statements.

After building dpq2 with the unit tests file libdpq2 can be executed. Option "--conninfo" may contains connection string as described in [PostgreSQL documentation] (

For default connection to DB type:

$ ./libdpq2 

Connection to usually available database "postgres":

$ ./libdpq2 --conninfo "dbname=postgres"

Network connection:

$ ./libdpq2 --conninfo "host= dbname=testdb user=testuser password=123123"


  • Async queries support
  • PostGIS binary data support
  • PostgreSQL arrays
  • Make code more transparent, CamelCased and Autodoc