.NET Core開發日誌——ADO.NET與SQL Server

在.NET世界，若是想要對數據庫進行操做，總少不了ADO.NET的身影。在.NET Core裏一樣離不開那些熟悉的類庫與API。這裏簡略地介紹下如何經過ADO.NET對SQL Server進行不一樣的處理。

System.Data.SqlClient

第一步先在項目工程中查看有無System.Data.SqlClient引用，若是沒有的話，能夠用如下三種方式安裝：

• Visual Studio上的可視化Nuget包管理工具(Manage NuGet Packages)，找到相應類庫，點擊安裝按鈕
• 一樣是Visual Studio上的包管理控制檯(Package Manager Console) 輸入命令，Install-Package System.Data.SqlClient
• 命令行界面(CLI) 中使用命令，dotnet add package System.Data.SqlClient

查詢

能夠使用最基礎的ExecuteReader方法：

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    conn.Open();
    using (var cmd = new SqlCommand("select top 10 * from [AdventureWorks2016CTP3].[Person].[Person]", conn))
    {
        using (var reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                Console.WriteLine(reader["FirstName"]);
            }
        }
    }
}

在.NET Core 2.0之後還能夠使用SqlDataAdapter與DataSet，看得出微軟在向後兼容方面作了很多工做：

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    var adapter = new SqlDataAdapter("select top 10 * from [AdventureWorks2016CTP3].[Person].[Person]", conn);
    var dataset = new DataSet();
    adapter.Fill(dataset);
    var dt = dataset.Tables[0];
    foreach (var item in dt.Rows)
    {
        var row = item as DataRow;
        Console.WriteLine(row["FirstName"]);
    }
}

插入

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    conn.Open();
    using (var cmd = new SqlCommand("insert into [AdventureWorks2016CTP3].[Person].[AddressType] (Name) values(@Name)", conn))
    {
        cmd.Parameters.AddWithValue("@Name", "Test");
        cmd.ExecuteNonQuery();
    }
}

更新

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    conn.Open();
    using (var cmd = new SqlCommand("update [AdventureWorks2016CTP3].[Person].[AddressType] set name = @Name where name = @Criterion", conn))
    {
        cmd.Parameters.AddWithValue("@Name", "Test2");
        cmd.Parameters.AddWithValue("@Criterion", "Test");
        cmd.ExecuteNonQuery();
    }
}

刪除

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    conn.Open();
    using (var cmd = new SqlCommand("delete [AdventureWorks2016CTP3].[Person].[AddressType] where name = @Name", conn))
    {
        cmd.Parameters.AddWithValue("@Name", "Test2");
        cmd.ExecuteNonQuery();
    }
}

存儲過程

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    conn.Open();
    using (var cmd = new SqlCommand("[AdventureWorks2016CTP3].[dbo].[uspGetEmployeeManagers]", conn))
    {
        cmd.CommandType = CommandType.StoredProcedure;
        cmd.Parameters.AddWithValue("@BusinessEntityID", 10);
        using (var reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                Console.WriteLine(reader["FirstName"]);
            }
        }
    }
}

視圖

使用上與普通的數據表沒有差異。

using (var conn = new SqlConnection("Server=.;Integrated Security=true"))
{
    conn.Open();
    using (var cmd = new SqlCommand("select top 10 * from [AdventureWorks2016CTP3].[HumanResources].[vEmployee]", conn))
    {
        using (var reader = cmd.ExecuteReader())
        {
            while (reader.Read())
            {
                Console.WriteLine(reader["FirstName"]);
            }
        }
    }
}

以上代碼例子裏的數據庫使用的是AdventureWorks Databases and Scripts for SQL Server 2016 CTP3