Encapsulated DBHelper (C #)

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C # links to SQL.

1. Link string configuration information is saved in app. Config

  <!--connect the database string    --<connectionStrings> <add name= "Dbstrconn" connectionstring= "Data source=.; Initial catalog= database; User id= username; password= password "/>  </connectionStrings>

2. Add System.Configuration Reference

3. Get the link string in DBHelper

/* * Get Connection Database String * This string exists in the App. Config app configuration file */private static string strconnection = Configurationmanager.connectionstrings ["Dbstrconn"].　　ConnectionString; Dbstrconn is the "name" name in app. Config

4.

1) ExecuteNonQuery method performs insert, modify, delete

　　

public static int toinupdel_executenonquery (String sql) {    //connection command    using (SqlConnection conn = new SqlConnection ( strconnection))    {       Conn. Open ();   Open the connection       using (SqlCommand cmd = conn. CreateCommand ())       {          //Execute SQL statement          cmd.commandtext = SQL;          Returns the number of rows affected by the return          cmd. ExecuteNonQuery ();       }    

2) ExecuteScalar Method execution Query

public static int toselect_executescalar (String sql) {    using (SqlConnection conn = new SqlConnection (strconnection) )    {        Conn. Open ();        using (SqlCommand cmd = conn. CreateCommand ())        {            cmd.commandtext = SQL;            Returns the result return            (int) cmd. ExecuteScalar ();}}}    

3) The DataTable is used to query the result less than the SQL

public static DataTable executedatatable (String sql) {       using (SqlConnection conn = new SqlConnection (strconnection))       {             Conn. Open ();             using (SqlCommand cmd = conn. CreateCommand ())             {                    cmd.commandtext = SQL;                    SqlDataAdapter adapter = new SqlDataAdapter (cmd);                    DataSet DataSet = new DataSet ();                    Adapter. Fill (dataset);                    return DataSet. Tables[0];             }       } }       

4) SqlDataReader need to be closed manually

public static SqlDataReader ExecuteReader (String sql) {    SqlConnection conn = new SqlConnection (strconnection);    SqlCommand cmd = new SqlCommand (sql,conn);    Try    {Conn.　　Open (); SqlDataReader reader = cmd.　　ExecuteReader (commandbehavior.closeconnection); CommandBehavior.CloseConnection automatically closes the connection return reader when the DataReader is closed;    }    catch (SqlException ex)    {throw ex;    }}

What is wrong welcome to point out or have any suggestions also line, we learn together.

Encapsulated DBHelper (C #)