C# Drivers YSQL

• YugabyteDB Npgsql Smart Driver
• PostgreSQL Npgsql Driver

Npgsql is an open source ADO.NET Data Provider for PostgreSQL; it allows programs written in C#, Visual Basic, and F# to access the YugabyteDB server. Npgsql is based on libpq and supports the SCRAM-SHA-256 authentication method.

For details on Npgsql, refer to the Npgsql documentation.

For building a sample C# application with Npgsql, see Connect an application.

Download the driver dependency

If you are using Visual Studio IDE, add the Npgsql package to your project as follows:

1. Right-click Dependencies and choose Manage Nuget Packages
2. Search for Npgsql and click Add Package

To add the Npgsql package to your project when not using an IDE, use the following dotnet command:

dotnet add package Npgsql

or any of the other methods mentioned on the nuget page for Npgsql.

Fundamentals

Learn how to perform common tasks required for C# application development using the Npgsql driver.

Connect to YugabyteDB database

After setting up the dependencies, implement the C# client application that uses the Npgsql driver to connect to your YugabyteDB cluster and run a query on the sample data.

Import Npgsql and use the NpgsqlConnection class to create the connection object to perform DDLs and DMLs against the database.

The following table describes the connection parameters for connecting to the YugabyteDB database.

The following is a basic example connection string for connecting to YugabyteDB.

var connStringBuilder = "Host=localhost;Port=5433;Database=yugabyte;Username=yugabyte;Password=password"
NpgsqlConnection conn = new NpgsqlConnection(connStringBuilder);

connStringBuilder.ServerCompatibilityMode = ServerCompatibilityMode.NoTypeLoading;

Server Compatibility Mode=NoTypeLoading;

Create table

Tables can be created in YugabyteDB by passing the CREATE TABLE DDL statement to the NpgsqlCommand class and getting a command object, then calling the ExecuteNonQuery() method using this command object.

CREATE TABLE employee (id int PRIMARY KEY, name varchar, age int, language varchar)

conn.Open();
NpgsqlCommand empCreateCmd = new NpgsqlCommand("CREATE TABLE employee (id int PRIMARY KEY, name varchar, age int, language varchar);", conn);
empCreateCmd.ExecuteNonQuery();

Read and write data

Insert data

To write data into YugabyteDB, execute the INSERT statement using the NpgsqlCommand class, get a command object, and then call the ExecuteNonQuery() method using this command object.

INSERT INTO employee (id, name, age, language) VALUES (1, 'John', 35, 'CSharp');

NpgsqlCommand empInsertCmd = new NpgsqlCommand("INSERT INTO employee (id, name, age, language) VALUES (1, 'John', 35, 'CSharp');", conn);
int numRows = empInsertCmd.ExecuteNonQuery();

Query data

To query data from YugabyteDB tables, execute the SELECT statement using the NpgsqlCommand class, get a command object, and then call the ExecuteReader() function using the object. Loop through the reader to get the list of returned rows.

SELECT * from employee where id=1;

NpgsqlCommand empPrepCmd = new NpgsqlCommand("SELECT name, age, language FROM employee WHERE id = @EmployeeId", conn);
empPrepCmd.Parameters.Add("@EmployeeId", NpgsqlTypes.NpgsqlDbType.Integer);

empPrepCmd.Parameters["@EmployeeId"].Value = 1;
NpgsqlDataReader reader = empPrepCmd.ExecuteReader();

Console.WriteLine("Query returned:\nName\tAge\tLanguage");
while (reader.Read())
{
    Console.WriteLine("{0}\t{1}\t{2}", reader.GetString(0), reader.GetInt32(1), reader.GetString(2));
}

Configure SSL/TLS

The following table describes the additional parameters the .NET Npgsql driver requires as part of the connection string when using SSL.

Npgsql supports SSL modes in different ways depending on the driver version, as shown in the following table.

The .NET Npgsql driver validates certificates differently from other PostgreSQL drivers as follows:

• Prior to version 6.0, when you specify SSL mode Require, you also need to specify RootCertificate, and the driver verifies the certificate by default (like the verify CA or verify full modes on other drivers), and fails for self-signed certificates.

  To use self-signed certificates, specify TrustServerCertificate=true, which bypasses walking the certificate chain to validate trust and hence works like other drivers' require mode. In this case, you don't need to specify the RootCertificate.

• For version 6.0 and later, the Require SSL mode requires explicitly setting the TrustServerCertificate field to true.

The following example shows how to build a connection string for connecting to a YugabyteDB cluster using the Require SSL mode.

var connStringBuilder = new NpgsqlConnectionStringBuilder();
    connStringBuilder.Host = "22420e3a-768b-43da-8dcb-xxxxxx.aws.ybdb.io";
    connStringBuilder.Port = 5433;
    connStringBuilder.SslMode = SslMode.Require;
    connStringBuilder.Username = "admin";
    connStringBuilder.Password = "xxxxxx";
    connStringBuilder.Database = "yugabyte";
    connStringBuilder.TrustServerCertificate = true;
    CRUD(connStringBuilder.ConnectionString);

The following example shows how to build a connection string for connecting to a YugabyteDB cluster using the VerifyCA and VerifyFull SSL modes.

var connStringBuilder = new NpgsqlConnectionStringBuilder();
    connStringBuilder.Host = "22420e3a-768b-43da-8dcb-xxxxxx.aws.ybdb.io";
    connStringBuilder.Port = 5433;
    connStringBuilder.SslMode = SslMode.VerifyCA;
    //or connStringBuilder.SslMode = SslMode.VerifyFull;
    connStringBuilder.RootCertificate = "/root.crt"; //Provide full path to your root CA.
    connStringBuilder.Username = "admin";
    connStringBuilder.Password = "xxxxxx";
    connStringBuilder.Database = "yugabyte";
    CRUD(connStringBuilder.ConnectionString);

For more information on TLS/SSL support, see Security and Encryption in the Npgsql documentation.

Compatibility matrix