对DataTable的困惑？

Question

DataTable可否更新从数据源中读取的部分数据，需要哪些必要条件？还有，如果我创建一个跟数据源中的表结构一样的DataTable，这样是否也可以更新数据源中的数据，谢谢

Answer 1

// 建表 SQL
            //CREATE TABLE [dbo].[Employee](
            //    [fldGuid] [uniqueidentifier] NOT NULL,
            //    [fldName] [nvarchar](50) COLLATE Chinese_PRC_CI_AS NOT NULL,
            //    [fldDescription] [nvarchar](500) COLLATE Chinese_PRC_CI_AS NOT NULL,
            // CONSTRAINT [PK_Employee] PRIMARY KEY CLUSTERED 
            //(
            //    [fldGuid] ASC
            //)WITH (IGNORE_DUP_KEY = OFF) ON [PRIMARY]
            //) ON [PRIMARY]

            string fConnectionString = @"server=XXY\SQLEXPRESS;database=XSample;Integrated Security=SSPI";
            string fCommandText = "SELECT fldGuid, fldName, fldDescription FROM Employee";

            using (SqlConnection connection = new SqlConnection(fConnectionString))
            {
                SqlDataAdapter adapter = new SqlDataAdapter();
                adapter.SelectCommand = new SqlCommand(fCommandText, connection);
                SqlCommandBuilder builder = new SqlCommandBuilder(adapter);

                connection.Open();

                DataSet dataSet = new DataSet();
                adapter.Fill(dataSet, "Employee");

                dataSet.Tables["Employee"].Rows.Add(new object[] { Guid.NewGuid(), "Name 01", "Description 01" });
                dataSet.Tables["Employee"].Rows.Add(new object[] { Guid.NewGuid(), "Name 02", "Description 02" });
                dataSet.Tables["Employee"].Rows.Add(new object[] { Guid.NewGuid(), "Name 03", "Description 03" });
                dataSet.Tables["Employee"].Rows.Add(new object[] { Guid.NewGuid(), "Name 04", "Description 04" });

                builder.GetUpdateCommand();
                adapter.Update(dataSet, "Employee");
            }

如果要更新的话要求 SelectCommand 还必须至少返回一个主键列或唯一的列， 建议您了解一个强类型 DataSet

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知识改变命运，奋斗成就人生!

Answer 2

你好！
     更新主要使用的是DbDataAdapter的Update方法，类似这样：

public
 DataSet CreateCmdsAndUpdate(DataSet dataSet, string
 connectionString,

    string
 queryString) 

{

    using
 (OleDbConnection connection = new
 OleDbConnection(connectionString))

    {

        OleDbDataAdapter adapter = new
 OleDbDataAdapter();

        adapter.SelectCommand = new
 OleDbCommand(queryString, connection);

        OleDbCommandBuilder builder = new
 OleDbCommandBuilder(adapter);



        connection.Open();



        DataSet customers = new
 DataSet();

        adapter.Fill(customers);



        //code to modify data in dataset here




        adapter.Update(customers);



        return
 customers;

    }

}

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周雪峰