C#判断表是否存在MySQL、PostgreSQL、SqlSer

MySQL

public static bool IsTableExists(string connectionString, string tblName)
{
    string sql = "SELECT table_name FROM information_schema.TABLES WHERE table_name =@tableName";
    string result = MySQLHelper.ExecuteScalar(connectionString,
        System.Data.CommandType.Text, sql,
        new MySqlParameter("tableName", tblName)) as string;
    return String.IsNullOrEmpty(result) ? false : true;
}

PostgreSQL

public static bool IsTableExists(string connectionString, string tblName)
{
    string sql = "select to_regclass(@tableName)";
    string result = PostgreSQLHelper.ExecuteScalar(connectionString, 
           System.Data.CommandType.Text, sql, 
           new NpgsqlParameter("tableName", tblName)) as string;
    return String.IsNullOrEmpty(result) ? false : true;
}

SqlServer

public static bool IsTableExists(string connectionString, string tblName)
{
    string sql = "if object_id(@tableName) is not null select 'ok' else select ''";
    string result = SqlHelper.ExecuteScalar(connectionString, 
        System.Data.CommandType.Text, sql, 
        new SqlParameter("tableName", tblName)) as string;
    return String.IsNullOrEmpty(result) ? false : true;
}