C# 获取数据库C中的表总数#
如何获取c#中的表总数。这就是我试过的。这是真的C# 获取数据库C中的表总数#,c#,sql-server,winforms,C#,Sql Server,Winforms,如何获取c#中的表总数。这就是我试过的。这是真的 conn = new MySqlConnection(); conn.ConnectionString = connString; conn.Open(); string queryss = "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'bluevels_local_sis'"; MySqlCommand cmdaa = new MySqlCommand
conn = new MySqlConnection();
conn.ConnectionString = connString;
conn.Open();
string queryss = "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'bluevels_local_sis'";
MySqlCommand cmdaa = new MySqlCommand(queryss, conn);
MySqlDataReader dataReaderxx = cmdaa.ExecuteReader();
dataReaderxx.Read();
MessageBox.Show(Convert.ToString(dataReaderxx.HasRows));
conn.Close();
您需要从返回的结果集中获取列值
dataReaderxx.Read();
dataReaderxx.GetInt32(0)
关闭,只需使用ExecuteScalar()
获取单个值。不需要数据读取器
string queryss = "SELECT COUNT(*) FROM information_schema.tables WHERE table_schema = 'bluevels_local_sis'";
using(conn = new MySqlConnection(connString)){
conn.Open();
MySqlCommand cmdaa = new MySqlCommand(queryss, conn);
MessageBox.Show(cmdaa.ExecuteScalar().ToString());
}
当结果只有一行和一列(如计数)时,使用
ExecuteScalar
而不是执行ExecuteReader
可以大大简化代码。ExecuteScalar将返回该值。