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Posted 15 Nov 2008
Licenced BSD

Using PostgreSQL in your C# (.NET) application (An introduction)

, 15 Nov 2008
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In this article, I would like to show you step by step how to use this fantastic database in your C# application.


In this article, I would like to show you the basics of using a PostgreSQL database in your .NET application. The reason why I'm doing this is the lack of PostgreSQL articles on CodeProject despite the fact that it is a very good RDBMS. I have used PostgreSQL back in the days when PHP was my main programming language, and I thought.... well, why not use it in my C# application.


I assume you have a basic knowledge of databases, SQL commands, and so on.

Why PostgreSQL

First and foremost, it's free*, in BSD-style freedom (both libre and gratis), which means you will not have license problems in your commercial applications. Next, you have a very good procedural language called PL/pgSQL (there are also the Java, Perl, Python, Tcl (and other) flavors). Lots of communities support it (large ones like Planet PostgreSQL, or blogs, for instance, "Depesz" blog), and finally, lot's of fun exploring this pearl of open source databases.

Installing PostgreSQL and the .NET data provider

First of all, go to the PostgreSQL website. PostgreSQL is known for having a very good documentation system. For the purposes of this article, I used PostgreSQL v.8.3.4 and PgAdmin III v. 1.8.4 (that comes bundled with PostgreSQL). Remember to install the database and PgAdmin III, but NOT Npgsql, since it comes with version 1.x and we're going to use v. 2.0. from a different package. Now, if you have a PostgreSQL server up and running (which is a really easy task), let's download some drivers. For this article, I have used NpgSQL2 built directly for MS .NET. When you download it, in the zip package (\bin directory), you will find Npgsql.dll, and that's the library we're looking for.

Playing with PgAdmin III

If you have ever worked with any DB-Management software like Aqua Data Studio, SQL Manager (I use the Lite version every day), or the MS Management Studio Express, you will find PgAdmin III really intuitive. It may not have that many gizmos as others, but it will do the job nicely. Here are a couple of daily tasks that you probably want to know how to do.

  1. Creating a new user (unless you really don't mind playing with a super-user account :-)):
  2. How to create new role on the server

  3. Creating a new database (fairly obvious, but nevertheless here it goes :-)):
  4. How to create new database in PgAdmin III

  5. Creating a table:
  6. How to create new table in PostgreSQL

  7. Adding stuff to tables (there are, of course, other ways, but I will let you explore this):
  8. How to add more tables

  9. If you are looking for an MS-SQL Identity, just make your column type serial, or look for sequence in the documentation. OK, to be completely honest, PgAdmin III still needs work... numbers may not appear if you add a row through the grid, but believe me, they are there :-). You will see them the next time you reload a window with the grid.
  10. If you looking for more hit documentation :-)

Making a database

Here is a SQL-script so we can make our test database. Remember to create a database and a user. My user for this article will be adrian.

CREATE TABLE simple_table
  id integer NOT NULL, -- SERIAL if like identity-like functionality
  tekst character varying(50),
  CONSTRAINT simple_table_pkey PRIMARY KEY (id)
ALTER TABLE simple_table OWNER TO adrian; -- my user

-- i drop Polish letters so i don't have to worry about codepage
INSERT INTO simple_table (id, tekst) VALUES (1, 'jaki tekst');
INSERT INTO simple_table (id, tekst) VALUES (2, 'jaki inny tekst');
INSERT INTO simple_table (id, tekst) VALUES (3, 'jeszcze inny tekst');

Using PostgreSQL in C#

Just make an empty Windows Forms application, and add a reference to Npgsql.dll, like shown in the picture:

Adding Npgsql provider

Baking a connection string PostgreSQL-style

A connection string in PostgreSQL is made by making keyword=value; pairs (Important: even the last element must end with a ';'). The most basic ones are:

  • Server - specifies the server location
  • User Id - the database user
  • Port - default is 5432
  • Password - the password for the database user
  • Database - the database name

Simple test application

using Npgsql;

namespace PostgreSQLTEst
    public partial class Form1 : Form
        private DataSet ds = new DataSet();
        private DataTable dt = new DataTable();
        public Form1()
        private void llOpenConnAndSelect_LinkClicked(object sender, 
                     LinkLabelLinkClickedEventArgs e)
                // PostgeSQL-style connection string
                string connstring = String.Format("Server={0};Port={1};" + 
                    "User Id={2};Password={3};Database={4};",
                    tbHost.Text, tbPort.Text, tbUser.Text, 
                    tbPass.Text, tbDataBaseName.Text );
                // Making connection with Npgsql provider
                NpgsqlConnection conn = new NpgsqlConnection(connstring);
                // quite complex sql statement
                string sql = "SELECT * FROM simple_table";
                // data adapter making request from our connection
                NpgsqlDataAdapter da = new NpgsqlDataAdapter(sql, conn);
                // i always reset DataSet before i do
                // something with it.... i don't know why :-)
                // filling DataSet with result from NpgsqlDataAdapter
                // since it C# DataSet can handle multiple tables, we will select first
                dt = ds.Tables[0];
                // connect grid to DataTable
                dataGridView1.DataSource = dt;
                // since we only showing the result we don't need connection anymore
            catch (Exception msg)
                // something went wrong, and you wanna know why

And the effect:

Working example

And, that's it! :D. Practice PostgreSQL and enjoy!

Final words

This article is for those who have used a database for a couple of months (or even years) and would like to taste something different. If you are looking for a solid, stable, secure, and relatively fast database - PostgreSQL is for you. It costs 0.00 $, it has some cool features (look into the documentation and you will find them), and it is free.

I hope that you enjoyed my article :-)

Really final words.... :-)

The project has two dependencies. The first is Npgsql.dll (provider) and the second is MultiCtrls (which is a DLL that was built in my other article). If something is wrong with the sources, please make references by hand (MultiCtrls is bundled with the ZIP file).


This article, along with any associated source code and files, is licensed under The BSD License


About the Author

Adrian Pasik
Software Developer Agilion Consulting
Poland Poland
I specialize at C#, developing Enterprise solutions. I have some knowledge of ASP.NET MVC - looking forward to use it together with Typescript.

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Comments and Discussions

GeneralMy vote of 4 Pin
dienius4-Jul-10 23:56
memberdienius4-Jul-10 23:56 
GeneralThank you [modified] Pin
alaindominique6-Jun-10 4:15
memberalaindominique6-Jun-10 4:15 
GeneralConnect postgres using c# Pin
kjhg3-Dec-09 23:56
memberkjhg3-Dec-09 23:56 
NewsPostgreSQL can support arabic fonts now Pin
Thabet Tech24-May-09 5:32
memberThabet Tech24-May-09 5:32 
GeneralFailed to establish a connection... Pin
Rodrigo Castilho11-May-09 9:04
memberRodrigo Castilho11-May-09 9:04 
QuestionImposible make "IsolationLevel.ReadUncommitted" Pin
DavidRRR11-Feb-09 11:22
memberDavidRRR11-Feb-09 11:22 
AnswerRe: Imposible make "IsolationLevel.ReadUncommitted" Pin
Adrian Pasik12-Feb-09 5:39
memberAdrian Pasik12-Feb-09 5:39 
GeneralRe: Imposible make "IsolationLevel.ReadUncommitted" Pin
liron.levi29-Mar-09 20:20
memberliron.levi29-Mar-09 20:20 
Actually - postgresql does not support the read-uncommited isolation level.

It converts read-uncommited to read-commited (the more restrictive level) and RepeatableRead to Serializable.

This behavior is due to postgresql multiversioning architecture.

The driver should have done this automatically (instead of throwing the exception).

GeneralGood article Pin
Donsw8-Jan-09 10:44
memberDonsw8-Jan-09 10:44 
QuestionHow to save a image file and put on a web page. Pin
DavidRRR11-Dec-08 10:57
memberDavidRRR11-Dec-08 10:57 
AnswerRe: How to save a image file and put on a web page. Pin
Adrian Pasik12-Dec-08 3:58
memberAdrian Pasik12-Dec-08 3:58 
Generalc# datasource Pin
Jan Bekaert20-Nov-08 9:31
memberJan Bekaert20-Nov-08 9:31 
GeneralRe: c# datasource Pin
Adrian Pasik20-Nov-08 9:52
memberAdrian Pasik20-Nov-08 9:52 
GeneralRe: c# datasource Pin
krepak4-Dec-08 19:03
memberkrepak4-Dec-08 19:03 
GeneralRe: c# datasource Pin
Muaath8025-Mar-12 19:29
memberMuaath8025-Mar-12 19:29 
GeneralGood selected subject Pin
Member 476538718-Nov-08 6:04
memberMember 476538718-Nov-08 6:04 
GeneralRe: Good selected subject Pin
Adrian Pasik18-Nov-08 9:08
memberAdrian Pasik18-Nov-08 9:08 
Generalgeneralbits [modified] Pin
Leblanc Meneses16-Nov-08 7:04
memberLeblanc Meneses16-Nov-08 7:04 

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