连接字符串

Server=address;Database=dataBaseName;Uid=username;Pwd=password;

更多连接方式

检查表是否存在

方法1

SELECT * 
FROM information_schema.tables
WHERE table_schema = 'yourdbName' 
    AND table_name = 'testtable'
LIMIT 1;

（默认table_schema 即数据库名称）
方法2

SELECT count(*)
FROM information_schema.tables
WHERE (TABLE_SCHEMA = 'your_db_name') AND (TABLE_NAME = 'name_of_table')

参考资料：
Check if table exists without using “select from”

获得表的自增长id当前最大值

select max(id) from tableName

参考资料：
Mysql获取最大自增ID（auto_increment）的五种方式及其特点

获取表的字段列表(EF)

string conn= "Server=address;Database=dataBaseName;Uid=username;Pwd=password;";
using(var _con= new MySqlConnection(conn))
{
	var lst = new List<string>();
	var sql = "select * from " + tableName + " where 1<0";
	using (var cmd = new MySqlCommand(sql, _con))
	{
		using (var r = cmd.ExecuteReader())
		{
			for (int i = 0; i < r.FieldCount; ++i)
			{
				lst.Add(r.GetName(i));
			}
		}
	}
}