.NET Core开发日志——ADO.NET与SQL Server

发布日期:2019-10-23

在.NET世界,如果想要对数据库进行操作,总少不了ADO.NET的身影。在.NET Core里同样离不开那些熟悉的类库与API。这里简略地介绍下如何通过ADO.NET对SQL Server进行不同的处理。

System.Data.SqlClient

第一步先在项目工程中查看有无System.Data.SqlClient引用,如果没有的话,可以用以下三种方式安装:

Visual Studio上的可视化Nuget包管理工具(Manage NuGet Packages),找到相应类库,点击安装按钮同样是Visual Studio上的包管理控制台(Package Manager Console) 输入命令,Install-Package System.Data.SqlClient命令行界面(CLI) 中使用命令,dotnet add package System.Data.SqlClient

查询

可以使用最基础的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以后还可以使用SqlDataAdapter与DataSet,看得出微软在向后兼容方面做了不少工作:

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(); }}

删除

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(); }}

存储过程

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"]); } } }}

视图

使用上与普通的数据表没有差别。

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"]); } } }}

以上代码例子里的数据库使用的是AdventureWorks Databases and Scripts for SQL Server 2016 CTP3