[C#] 数据库操作 - Insert, Read, Delete, Update

string ConnectionString = @"Provider=Microsoft.ACE.OLEDB.12.0;Data Source=" + System.Web.HttpContext.Current.Server.MapPath("\\CMIT_SH_DATA\\CMIT_SH_MMS.accdb");
public DataTable ReadDB(string SqlCmdString)
{
DataTable dt = new DataTable();

using (OleDbDataAdapter adapter = new OleDbDataAdapter(SqlCmdString, ConnectionString))
{
adapter.Fill(dt);
}
return dt;
}

public void InsertDB(string SqlCmdString)
{

using (OleDbConnection conn = new OleDbConnection(ConnectionString))
{
conn.Open();

using (OleDbCommand cmd = conn.CreateCommand())
{
cmd.CommandText = SqlCmdString;

cmd.ExecuteNonQuery();
}
}
}

public void updateDb( string SqlCmdString)
{
using (OleDbConnection conn = new OleDbConnection(ConnectionString))
{
conn.Open();

using (OleDbCommand cmd = conn.CreateCommand())
{
cmd.CommandText = SqlCmdString;

cmd.ExecuteNonQuery();
}
}
}

public void DeleteDb(string SqlCmdString)
{
using (OleDbConnection conn = new OleDbConnection(ConnectionString))
{
conn.Open();

using (OleDbCommand cmd = conn.CreateCommand())
{
cmd.CommandText = SqlCmdString;

cmd.ExecuteNonQuery();
}
}
}