Quickstart: Maak verbinding en voer query's uit met Microsoft.Data.SqlClient

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Voer in een lege map deze commando's uit:

dotnet new console --framework net10.0 --name SqlClientQuickstart
cd SqlClientQuickstart
dotnet add package Microsoft.Data.SqlClient --version 7.1.1
dotnet add package Microsoft.Data.SqlClient.Extensions.Azure --version 7.1.1

De consoletemplate biedt geen .NET Framework-doelplatforms aan. Maak in een lege map het project aan:

dotnet new console --framework net10.0 --name SqlClientQuickstart
cd SqlClientQuickstart

Vervang de inhoud van SqlClientQuickstart.csproj door dit projectbestand:

<Project Sdk="Microsoft.NET.Sdk">

  <PropertyGroup>
    <OutputType>Exe</OutputType>
    <TargetFramework>net481</TargetFramework>
  </PropertyGroup>

</Project>

Voeg dan de pakketten toe:

dotnet add package Microsoft.Data.SqlClient --version 7.1.1
dotnet add package Microsoft.Data.SqlClient.Extensions.Azure --version 7.1.1

Vervang de inhoud van Program.cs met deze code:

using System.Data;
using Microsoft.Data.SqlClient;

string? connectionString =
    Environment.GetEnvironmentVariable("SQL_CONNECTION_STRING");

if (string.IsNullOrWhiteSpace(connectionString))
{
    Console.Error.WriteLine(
        "Set the SQL_CONNECTION_STRING environment variable.");
    return 1;
}

using var cancellation = new CancellationTokenSource();
Console.CancelKeyPress += (_, eventArgs) =>
{
    eventArgs.Cancel = true;
    cancellation.Cancel();
};

try
{
    await using var connection = new SqlConnection(connectionString);
    await connection.OpenAsync(cancellation.Token);

    const string createTableSql = """
        IF OBJECT_ID(N'dbo.SqlClientQuickstart', N'U') IS NULL
        BEGIN
            CREATE TABLE dbo.SqlClientQuickstart
            (
                Id int IDENTITY(1, 1) PRIMARY KEY,
                Message nvarchar(200) NOT NULL,
                CreatedAt datetimeoffset NOT NULL
                    CONSTRAINT DF_SqlClientQuickstart_CreatedAt
                    DEFAULT sysdatetimeoffset()
            );
        END;
        """;

    await using (var createCommand =
        new SqlCommand(createTableSql, connection) { CommandTimeout = 30 })
    {
        await createCommand.ExecuteNonQueryAsync(cancellation.Token);
    }

    const string insertSql = """
        INSERT INTO dbo.SqlClientQuickstart (Message)
        OUTPUT INSERTED.Id
        VALUES (@message);
        """;

    string[] messages =
    [
        "Hello from Microsoft.Data.SqlClient",
        "Parameters keep values out of the SQL text"
    ];

    int firstId = 0;
    await using (var insertCommand =
        new SqlCommand(insertSql, connection) { CommandTimeout = 30 })
    {
        SqlParameter messageParameter =
            insertCommand.Parameters.Add("@message", SqlDbType.NVarChar, 200);

        foreach (string message in messages)
        {
            messageParameter.Value = message;
            int id = (int)(await insertCommand.ExecuteScalarAsync(
                cancellation.Token))!;
            Console.WriteLine($"Inserted row {id}.");
            firstId = firstId == 0 ? id : firstId;
        }
    }

    const string querySql = """
        SELECT Id, Message, CreatedAt
        FROM dbo.SqlClientQuickstart
        WHERE Id >= @firstId
        ORDER BY Id;
        """;

    await using var queryCommand =
        new SqlCommand(querySql, connection) { CommandTimeout = 30 };
    queryCommand.Parameters.Add("@firstId", SqlDbType.Int).Value = firstId;

    await using SqlDataReader reader =
        await queryCommand.ExecuteReaderAsync(cancellation.Token);

    while (await reader.ReadAsync(cancellation.Token))
    {
        Console.WriteLine(
            $"{reader.GetInt32(0)}: {reader.GetString(1)} " +
            $"(created {reader.GetDateTimeOffset(2):u})");
    }

    return 0;
}
catch (OperationCanceledException)
{
    Console.Error.WriteLine("The operation was canceled.");
    return 2;
}
catch (SqlException ex)
{
    Console.Error.WriteLine(
        $"SQL error {ex.Number}, connection {ex.ClientConnectionId}: " +
        ex.Message);
    if (ex.InnerException is not null)
    {
        Console.Error.WriteLine(ex.InnerException.Message);
    }
    return 3;
}

Vervang de inhoud van Program.cs met deze code:

using System;
using System.Data;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.Data.SqlClient;

class Program
{
    static async Task<int> Main()
    {
        string connectionString =
            Environment.GetEnvironmentVariable("SQL_CONNECTION_STRING");

        if (string.IsNullOrWhiteSpace(connectionString))
        {
            Console.Error.WriteLine(
                "Set the SQL_CONNECTION_STRING environment variable.");
            return 1;
        }

        using (var cancellation = new CancellationTokenSource())
        {
            Console.CancelKeyPress += (sender, eventArgs) =>
            {
                eventArgs.Cancel = true;
                cancellation.Cancel();
            };

            try
            {
                await RunAsync(connectionString, cancellation.Token);
                return 0;
            }
            catch (OperationCanceledException)
            {
                Console.Error.WriteLine("The operation was canceled.");
                return 2;
            }
            catch (SqlException ex)
            {
                Console.Error.WriteLine(
                    $"SQL error {ex.Number}, connection {ex.ClientConnectionId}: " +
                    ex.Message);
                if (ex.InnerException != null)
                {
                    Console.Error.WriteLine(ex.InnerException.Message);
                }
                return 3;
            }
        }
    }

    static async Task RunAsync(string connectionString, CancellationToken token)
    {
        using (var connection = new SqlConnection(connectionString))
        {
            await connection.OpenAsync(token);

            const string createTableSql = @"
IF OBJECT_ID(N'dbo.SqlClientQuickstart', N'U') IS NULL
BEGIN
    CREATE TABLE dbo.SqlClientQuickstart
    (
        Id int IDENTITY(1, 1) PRIMARY KEY,
        Message nvarchar(200) NOT NULL,
        CreatedAt datetimeoffset NOT NULL
            CONSTRAINT DF_SqlClientQuickstart_CreatedAt
            DEFAULT sysdatetimeoffset()
    );
END;";

            using (var createCommand =
                new SqlCommand(createTableSql, connection) { CommandTimeout = 30 })
            {
                await createCommand.ExecuteNonQueryAsync(token);
            }

            const string insertSql = @"
INSERT INTO dbo.SqlClientQuickstart (Message)
OUTPUT INSERTED.Id
VALUES (@message);";

            string[] messages =
            {
                "Hello from Microsoft.Data.SqlClient",
                "Parameters keep values out of the SQL text"
            };

            int firstId = 0;
            using (var insertCommand =
                new SqlCommand(insertSql, connection) { CommandTimeout = 30 })
            {
                SqlParameter messageParameter =
                    insertCommand.Parameters.Add("@message", SqlDbType.NVarChar, 200);

                foreach (string message in messages)
                {
                    messageParameter.Value = message;
                    int id = (int)await insertCommand.ExecuteScalarAsync(token);
                    Console.WriteLine($"Inserted row {id}.");
                    firstId = firstId == 0 ? id : firstId;
                }
            }

            const string querySql = @"
SELECT Id, Message, CreatedAt
FROM dbo.SqlClientQuickstart
WHERE Id >= @firstId
ORDER BY Id;";

            using (var queryCommand =
                new SqlCommand(querySql, connection) { CommandTimeout = 30 })
            {
                queryCommand.Parameters.Add("@firstId", SqlDbType.Int).Value = firstId;

                using (SqlDataReader reader =
                    await queryCommand.ExecuteReaderAsync(token))
                {
                    while (await reader.ReadAsync(token))
                    {
                        Console.WriteLine(
                            $"{reader.GetInt32(0)}: {reader.GetString(1)} " +
                            $"(created {reader.GetDateTimeOffset(2):u})");
                    }
                }
            }
        }
    }
}