If you need to choose which data provider for PostgreSQL to use with dotConnect Universal, we recommend using dotConnect for PostgreSQL because of its obvious advantages. This article provides a brief overview of dotConnect for PostgreSQL, describes some useful features and helps you get started quickly.

• Overview
• Compatibility
• Deployment
• Typical Connection String
• Quick Start Steps
• Special Features
• UniSQL Notes
• UniDbType Map
• Additional Information

Overview

dotConnect for PostgreSQL is a full-featured 100% managed ADO.NET data provider for the .NET Framework and the .NET Compact Framework. dotConnect for PostgreSQL is acknowledged as the leading ADO.NET data provider for PostgreSQL, and it has many advantages over any rival product. The main features of dotConnect for PostgreSQL are:

• High performance
• Easy deployment
• SSL and SSH connections
• Comprehensive support for the latest versions of PostgreSQL server
• Advanced design-time editors and wizards

The full list of dotConnect for PostgreSQL features can be found on the product page.

The Developer Edition of dotConnect Universal includes dotConnect for PostgreSQL as a bundled provider. The Trial Edition includes trial dotConnect for PostgreSQL Data Provider as well. For Express Edition of dotConnect Universal, dotConnect for PostgreSQL Data Provider should be purchased and installed separately.

Compatibility

dotConnect Universal is compatible with dotConnect for PostgreSQL version 4.00 and above.

Deployment

To deploy applications written with dotConnect Universal, copy the run-time assemblies Devart.Data.Universal.dll and Devart.Data.Universal.PostgreSql.dll to target machine. If you are using the standalone (not bundled) dotConnect for PostgreSQL Data Provider, you will also have to deploy its Devart.Data.PostgreSql.dll assembly.

These assemblies can be registered at the Global Assembly Cache (GAC) for the appropriate .NET Framework or placed in the folder of your application.

For web projects, you may also need to deploy the Devart.Data.Universal.Web.dll, Devart.Data.PostgreSql.Web.dll and App_Licenses.dll assemblies. The *.Web.dll assemblies are required for using the ASP.NET Provider Model and the App_Licenses.dll assembly is a part of licensing mechanism.

Web projects are usually run as partially trusted code. dotConnect Universal and dotConnect for PostgreSQL require medium trust plus ReflectionPermission and SocketPermission.

Connection String

Suppose you want to connect to a PostgreSQL server running on the host server, at the port 5432, with the user name postgres and the password mypassword. Suppose also that you would like to work within schema Public and use postgres as the default database. In this case your connection string would look like this:

Provider=PostgreSQL;host=server;port=5432;user=postgres;password=mypassword;initial schema=Public;database=postgres

The initial schema parameter is Public by default; the port parameter defaults to 5432 as well. If the database parameter is not specified, it is assumed that name of the database is same as user name. So basically you need only host name, user name and password:

Provider=PostgreSQL;host=server;user=postgres;password=mypassword

The following table enumerates most important connection string parameters.

Quick Start Steps

To get up and running quickly, you have to perform the following steps:

1. Embed licensing information into your application. If you use bundled dotConnect for PostgreSQL version, you need only dotConnect Universal licensing. If you use a standalone dotConnect for PostgreSQL installation, embed the licensing information about both dotConnect Universal and dotConnect for PostgreSQL data providers. For more details on licensing refer to the Licensing article. For bundled providers it may be enough to drop a UniConnection component onto a form designer to embed the licensing information.
2. Create a UniConnection object.
3. Set the ConnectionString property of the UniConnection object to a string containing the part Provider=PostgreSQL.
4. Create a UniCommand object and link it to the UniConnection object.
5. Open the connection.

That's all you need to start executing queries on the server. Below is a code fragment that illustrates steps 2-5. It also shows how to perform INSERT and SELECT operations.

UniConnection connection = new UniConnection("Provider=PostgreSQL;host=server;user=postgres;password=mypassword");
try {
  UniCommand cmd = connection.CreateCommand();
  cmd.CommandText = "INSERT INTO dept (DeptNo, Dname, Loc) VALUES (:DeptNo, :DName, :Loc)";
  UniParameter parameter = cmd.Parameters.Add("DeptNo", UniDbType.Int);
  parameter.Value = 150;
  parameter = cmd.Parameters.Add("DName", UniDbType.VarChar);
  parameter.Value = "DEPTNAME";
  cmd.Parameters.Add(parameter);
  parameter = cmd.Parameters.Add("Loc", UniDbType.VarChar);
  parameter.Value = "LOCATION";
  cmd.Parameters.Add(parameter);
  connection.Open();
  cmd.ExecuteNonQuery();
}
finally {
  connection.Close();
}

...

DataSet dataSet = new DataSet();
UniDataAdapter da = new UniDataAdapter("SELECT * FROM dept", "Provider=PostgreSQL;host=server;user=postgres;password=mypassword");
da.Fill(dataSet, "Dept");

Dim connection As Devart.Data.Universal.UniConnection = New _
  Devart.Data.Universal.UniConnection("Provider=PostgreSQL;host=server;user=postgres;password=mypassword")
Try
  Dim cmd As UniCommand = connection.CreateCommand()
  cmd.CommandText = "INSERT INTO dept (DeptNo, DName, Loc) VALUES (:DeptNo, :DName, :Loc)"
  Dim parameter As Devart.Data.Universal.UniParameter = cmd.Parameters.Add("DEPTNO", UniDbType.Int)
  parameter.Value = 150
  parameter = cmd.Parameters.Add("DName", UniDbType.VarChar)
  parameter.Value = "DEPTNAME"
  parameter = cmd.Parameters.Add("Loc", UniDbType.VarChar)
  parameter.Value = "LOCATION"
  connection.Open()
  cmd.ExecuteNonQuery()
Finally
  connection.Close()
End Try

...

Dim dataSet As DataSet = New DataSet()
Dim da As UniDataAdapter = New UniDataAdapter("Provider=PostgreSQL;host=server;user=postgres;password=mypassword")
da.Fill(dataSet, "Dept")

Special Features

dotConnect Universal supports handling PostgreSQL BLOBs. For detailed information on how to work with BLOB objects, refer to the Working with BLOB Data article.

dotConnect Universal supports using the UniDecimal structure with PostgreSQL. Use the reference to find out how to manage big numbers on client side.

It is also possible to take advantage of special network capabilities of dotConnect for PostgreSQL by setting up the connection string parameters. This way you can enable:

• SSL encryption
• SSH forwarding

UniSQL Notes

dotConnect for PostgreSQL supports all features of UniSQL, except for the DATEDIFF unified function name. Use PostgreSQL and PostgreSQLDirect predefined macros to build conditional UniSQL statements. For more information refer to the UniSQL topic.

UniDbType Map

The following table shows how the UniDbType enumeration maps to the PostgreSQL database type.

Additional Information

For more information on dotConnect for PostgreSQL Data Provider please visit the following locations:

• Product home page at www.devart.com/dotconnect/postgresql
• Product downloads page at www.devart.com/dotconnect/postgresql/download.html to obtain the latest documentation
• Discussion forum at www.devart.com/forums/viewforum.php?f=3 to ask for help or report a bug

See Also

Using dotConnect Universal with SQL Client  | Using dotConnect Universal with dotConnect for Oracle  | Using dotConnect Universal with dotConnect for MySQL  | Using dotConnect Universal with dotConnect for SQLite