Database 2_sqlHelper and sqlhelper access the database

Database 2_sqlHelper and sqlhelper access the database

Encapsulate an affected row

1 public static int ExcuteNonQuery (string sqlText, params SqlParameter [] parameters) 2 {3 using (SqlConnection conn = new SqlConnection (GetSqlConnectionString ())) 4 {5 using (SqlCommand cmd = conn. createCommand () 6 {7 conn. open (); 8 cmd. commandText = sqlText; 9 cmd. parameters. addRange (parameters); // Add the parameter to the cmd command. 10 return cmd. ExecuteNonQuery (); 11} 12} 13}

Execute SQL. Returns the value of the first column in the first row of the query result.

1 # region Execute SQL. Returns the value of 2 3 public static object ExcuteScalar (string sqlText, params SqlParameter [] parameters) in the first column of the First row in the query result) 4 {5 using (SqlConnection conn = new SqlConnection (GetSqlConnectionString () 6 {7 using (SqlCommand cmd = conn. createCommand () 8 {9 conn. open (); 10 cmd. commandText = sqlText; 11 cmd. parameters. addRange (parameters); 12 return cmd. executeScalar (); 13} 14} 15} 16 17 public static T ExcuteScalar <T> (string sqlText, params SqlParameter [] parameters) 18 // where T: UserInfo must inherit a certain type 19 // where T: class // must be class 20 // where T: new () // requires T to have a default constructor 21 22 // where can be of the T type, must be a class, A constructor is required. A class or interface must be inherited or implemented. 23 {24 using (SqlConnection conn = new SqlConnection (GetSqlConnectionString () 25 {26 using (SqlCommand cmd = conn. createCommand () 27 {28 conn. open (); 29 cmd. commandText = sqlText; 30 cmd. parameters. addRange (parameters); 31 return (T) cmd. executeScalar (); 32 // int? I = 0; 33 // object num = I; 34 // I = num as int ?; 35} 36} 37} 38 # endregion

Execute SQL to return a DataTable

 1   public static DataTable ExcuteDataTable(string sqlText, params SqlParameter[] parameters) 2         { 3             using (SqlDataAdapter adapter = new SqlDataAdapter(sqlText, GetSqlConnectionString())) 4             { 5                 DataTable dt =new DataTable(); 6                 adapter.SelectCommand.Parameters.AddRange(parameters); 7                 adapter.Fill(dt); 8                 return dt; 9             }10         }

Execute the SQL script and return a SqlDataReader

1 public static SqlDataReader ExucteReader (string sqlText, params SqlParameter [] parameters) 2 {3 // SqlDataReader requires that it exclusively occupies its SqlConnection object when reading data, sqlConnection must be in the Open state. 4 SqlConnection conn = new SqlConnection (GetSqlConnectionString (); // do not release the connection because the connection must be enabled later. 5 SqlCommand cmd = conn. createCommand (); 6 conn. open (); 7 cmd. commandText = sqlText; 8 cmd. parameters. addRange (parameters); 9 // CommandBehavior. closeConnection: indicates that when SqlDataReader is released, the SqlConnection object is also released. 10 return cmd. ExecuteReader (CommandBehavior. CloseConnection );

 

Also assigned this piece is also can be referred to, the above is based on EF to determine the http://www.cnblogs.com/lishuangzhe/archive/2013/08/26/SqlHelper.html