dpq2 0.2.3

Medium-level binding to the PostgreSQL database


To use this package, run the following command in your project's root directory:

Manual usage
Put the following dependency into your project's dependences section:

dpq2

Build Status Coverage Status

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

It adds only tiny overhead to the original low level library libpq but make convenient use PostgreSQL from D.

Features

  • Arguments list support
  • Async queries support
  • 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")
  • Access to PostgreSQL's multidimensional arrays
  • LISTEN/NOTIFY support

Building

Bindings for libpq can be static or dynamic.

The static bindings are generated by default. Add --config=dynamic to the dub parameters to generate dynamic bindings.

Example

#!/usr/bin/env rdmd

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

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

    // Only text query result can be obtained by this call:
    auto s = conn.exec(
        "SELECT now() as current_time, 'abc'::text as field_name, "
        "123 as field_3, 456.78 as field_4"
        );
    
    writeln( "Text query result: ", s[0][3].as!PGtext );
    
    // Separated arguments query with binary result:
    QueryParams p;
    p.sqlCommand = "SELECT "~
        "$1::double precision as double_field, "~
        "$2::text, "~
        "$3::text as null_field, "~
        "array['first', 'second', NULL]::text[] as array_field, "~
        "$4::integer[] as multi_array";
    
    p.args.length = 4;
    
    p.args[0].value = "-1234.56789012345";
    p.args[1].value = "first line\nsecond line";
    p.args[2].value = null;
    p.args[3].value = "{{1, 2, 3}, {4, 5, 6}}";
    
    auto r = conn.exec(p);
    
    writeln( "0: ", r[0]["double_field"].as!PGdouble_precision );
    writeln( "1: ", r[0][1].as!PGtext );
    writeln( "2.1 isNull: ", r[0][2].isNull );
    writeln( "2.2 isNULL: ", r[0].isNULL(2) );
    writeln( "3.1: ", r[0][3].asArray[0].as!PGtext );
    writeln( "3.2: ", r[0][3].asArray[1].as!PGtext );
    writeln( "3.3: ", r[0]["array_field"].asArray[2].isNull );
    writeln( "3.4: ", r[0]["array_field"].asArray.isNULL(2) );
    writeln( "4: ", r[0]["multi_array"].asArray.getValue(1, 2).as!PGinteger );
    
    version(LDC) destroy(r); // before Derelict unloads its bindings (prevents SIGSEGV)
}

####Compile and run:

$ cd example
$ dub build --build=release
$ sudo -u postgres ./dpq2-example
Text query result: 456.78
0: -1234.57
1: first line
second line
2.1 isNull: true
2.2 isNULL: true
3.1: first
3.2: second
3.3: true
3.4: true
4: 6

TODO

  • Timestamp type support
  • PostGIS binary data support
  • Binary arguments types
Authors:
  • Denis Feklushkin
  • Anton Gushcha
Dependencies:
derelict-pq
Versions:
1.1.6-rc.1 2023-Mar-29
1.1.5 2023-Mar-19
1.1.4-rc.1 2022-Dec-07
1.1.3 2022-Nov-24
1.1.2 2022-Nov-24
Show all 176 versions
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Score:
4.5
Short URL:
dpq2.dub.pm