This tutorial shows you how build a simple C# (.NET) application with CockroachDB using a PostgreSQL-compatible driver.
We have tested the .NET Npgsql driver enough to claim beta-level support, so that driver is featured here. If you encounter problems, please open an issue with details to help us make progress toward full support.
Choose the instructions that correspond to whether your cluster is secure or insecure:
Step 1. Create a .NET project
$ dotnet new console -o cockroachdb-test-app
$ cd cockroachdb-test-app
The dotnet command creates a new app of type console. The -o parameter creates a directory named cockroachdb-test-app where your app will be stored and populates it with the required files. The cd cockroachdb-test-app command puts you into the newly created app directory.
Step 2. Install the Npgsql driver
Install the latest version of the Npgsql driver into the .NET project using the built-in nuget package manager:
$ dotnet add package Npgsql
## Step 3. Create the `maxroach` user and `bank` database {% include {{page.version.version}}/app/create-maxroach-user-and-bank-database.md %} ## Step 4. Generate a certificate for the `maxroach` user Create a certificate and key for the `maxroach` user by running the following command. The code samples will run as this user. {% include copy-clipboard.html %} ~~~ shell $ cockroach cert create-client maxroach --certs-dir=certs --ca-key=my-safe-directory/ca.key ~~~ ## Step 5. Convert the key file for use by C# programs The private key generated for user `maxroach` by CockroachDB is [PEM encoded](https://tools.ietf.org/html/rfc1421). To read the key in a C# application, you will need to convert it into PKCS#12 format. To convert the key to PKCS#12 format, run the following OpenSSL command on the `maxroach` user's key file in the directory where you stored your certificates: {% include copy-clipboard.html %} ~~~ shell $ openssl pkcs12 -inkey client.maxroach.key -password pass: -in client.maxroach.crt -export -out client.maxroach.pfx ~~~ As of December 2018, you need to provide a password for this to work on macOS. See
. ## Step 6. Run the C# code Now that you have created a database and set up encryption keys, in this section you will: - [Create a table and insert some rows](#basic-example) - [Execute a batch of statements as a transaction](#transaction-example-with-retry-logic) ### Basic example Replace the contents of `cockroachdb-test-app/Program.cs` with the following code: {% include copy-clipboard.html %} ~~~ csharp {% include {{ page.version.version }}/app/basic-sample.cs %} ~~~ Then, run the code to again connect as the `maxroach` user. This time, execute a batch of statements as an atomic transaction to transfer funds from one account to another, where all included statements are either committed or aborted: {% include copy-clipboard.html %} ~~~ shell $ dotnet run ~~~ The output should be: ~~~ Initial balances: account 1: 1000 account 2: 250 ~~~ ### Transaction example (with retry logic) Open `cockroachdb-test-app/Program.cs` again and replace the contents with the code shown below. {% include {{page.version.version}}/client-transaction-retry.md %} {% include copy-clipboard.html %} ~~~ csharp {% include {{ page.version.version }}/app/txn-sample.cs %} ~~~ Then, run the code to connect as the `maxroach` user. This time, execute a batch of statements as an atomic transaction to transfer funds from one account to another, where all included statements are either committed or aborted: {% include copy-clipboard.html %} ~~~ shell $ dotnet run ~~~ The output should be: ~~~ Initial balances: account 1: 1000 account 2: 250 Final balances: account 1: 900 account 2: 350 ~~~ However, if you want to verify that funds were transferred from one account to another, use the [built-in SQL client](use-the-built-in-sql-client.html): {% include copy-clipboard.html %} ~~~ shell $ cockroach sql --certs-dir=certs --database=bank -e 'SELECT id, balance FROM accounts' ~~~ ~~~ id | balance +----+---------+ 1 | 900 2 | 350 (2 rows) ~~~
## Step 3. Create the `maxroach` user and `bank` database {% include {{page.version.version}}/app/insecure/create-maxroach-user-and-bank-database.md %} ## Step 4. Run the C# code Now that you have created a database and set up encryption keys, in this section you will: - [Create a table and insert some rows](#basic2) - [Execute a batch of statements as a transaction](#transaction2)
### Basic example Replace the contents of `cockroachdb-test-app/Program.cs` with the following code: {% include copy-clipboard.html %} ~~~ csharp {% include {{ page.version.version }}/app/insecure/basic-sample.cs %} ~~~ Then, run the code to connect as the `maxroach` user and execute some basic SQL statements: creating a table, inserting rows, and reading and printing the rows. {% include copy-clipboard.html %} ~~~ shell $ dotnet run ~~~ The output should be: ~~~ Initial balances: account 1: 1000 account 2: 250 ~~~
### Transaction example (with retry logic) Open `cockroachdb-test-app/Program.cs` again and replace the contents with the code shown below. {% include {{page.version.version}}/client-transaction-retry.md %} {% include copy-clipboard.html %} ~~~ csharp {% include {{ page.version.version }}/app/insecure/txn-sample.cs %} ~~~ Then, run the code to connect as the `maxroach` user. This time, execute a batch of statements as an atomic transaction to transfer funds from one account to another, where all included statements are either committed or aborted: {% include copy-clipboard.html %} ~~~ shell $ dotnet run ~~~ The output should be: ~~~ Initial balances: account 1: 1000 account 2: 250 Final balances: account 1: 900 account 2: 350 ~~~ However, if you want to verify that funds were transferred from one account to another, use the [built-in SQL client](use-the-built-in-sql-client.html): {% include copy-clipboard.html %} ~~~ shell $ cockroach sql --insecure --database=bank -e 'SELECT id, balance FROM accounts' ~~~ ~~~ id | balance +----+---------+ 1 | 900 2 | 350 (2 rows) ~~~