ADO. NET acquires data (DataSet) and the schema instance of the table, ado. netdataset

ADO. NET acquires data (DataSet) and the schema instance of the table, ado. netdataset

The general method for obtaining DataSet through ADO. NET is as follows:

using System.Configuration;using System.Data;using System.Data.SqlClient;public class SQLHelper{ private static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["Default"].ConnectionString; public static DataSet GetDataSet(string sql) {  using (SqlConnection conn =new SqlConnection(ConnectionString))  {   SqlCommand cmd = new SqlCommand(sql, conn);   SqlDataAdapter adapter = new SqlDataAdapter(cmd);   DataSet ds = new DataSet();   conn.Open();   adapter.Fill(ds);   return ds;  } }}

<?xml version="1.0" encoding="utf-8" ?><configuration> <connectionStrings> <add name="Default" connectionString="Data Source=.;Initial Catalog=EFDb;Integrated Security=true"/> </connectionStrings></configuration>

Here we need to obtain the primary key information of the DataTable. When debugging, we find that there is no primary key information, and the actual database has a primary key (Id)

Set the attribute MissingSchemaAction to System. Data. MissingSchemaAction. AddWithKey for SqlDataAdapter.

The modified SQLHelper is

using System.Configuration;using System.Data;using System.Data.SqlClient;public class SQLHelper{ private static readonly string ConnectionString = ConfigurationManager.ConnectionStrings["Default"].ConnectionString; public static DataSet GetDataSet(string sql) {  using (SqlConnection conn =new SqlConnection(ConnectionString))  {   SqlCommand cmd = new SqlCommand(sql, conn);   SqlDataAdapter adapter = new SqlDataAdapter(cmd);   adapter.MissingSchemaAction = MissingSchemaAction.AddWithKey;   DataSet ds = new DataSet();   conn.Open();   adapter.Fill(ds);   return ds;  } }}

The above architecture example for obtaining data from ADO. NET (DataSet) and tables is all the content shared by Alibaba Cloud. I hope you can give us a reference and support for more customers.