Mysql 如何从多个表中删除productid
我想在单击按钮时删除一个产品id，我只能删除1个表如何处理我的查询Mysql 如何从多个表中删除productid,mysql,asp.net,Mysql,Asp.net,我想在单击按钮时删除一个产品id，我只能删除1个表如何处理我的查询 protected void btnDelete_Click(object sender, EventArgs e) { string connection = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString; SqlConnection connection1
protected void btnDelete_Click(object sender, EventArgs e)
{
string connection = ConfigurationManager.ConnectionStrings["ConnectionString"].ConnectionString;
SqlConnection connection1 = new SqlConnection(connection);
string sqlStatement = "DELETE FROM Product WHERE ProductID = @pid";
try
{
connection1.Open();
SqlCommand cmd = new SqlCommand(sqlStatement, connection1);
cmd.Parameters.AddWithValue("@pid", Id);
cmd.CommandType = CommandType.Text;
cmd.ExecuteNonQuery();
}
finally
{
connection1.Close();
}
}
或者，您可以在一个查询中执行此操作，而无需级联 为简洁起见，请考虑隐藏以下链接表
SELECT * FROM recipes;
+-----------+-------------------------+
| recipe_id | recipe |
+-----------+-------------------------+
| 1 | Macaroni & Cheese |
| 2 | Cheese on Toast |
| 3 | Beans on Toast |
| 4 | Cheese & Beans on Toast |
| 5 | Toast & Jam |
| 6 | Humus |
+-----------+-------------------------+
SELECT * FROM ingredients;
+---------------+------------+
| ingredient_id | ingredient |
+---------------+------------+
| 1 | Macaroni |
| 2 | Cheese |
| 3 | Beans |
| 4 | Toast |
| 5 | Jam |
| 6 | Chickpeas |
| 7 | Tahini |
+---------------+------------+
SELECT r.*
, i.*
FROM recipes r
JOIN recipe_ingredient ri
ON ri.recipe_id = r.recipe_id
JOIN ingredients i
ON i.ingredient_id = ri.ingredient_id;
+-----------+-------------------------+---------------+------------+
| recipe_id | recipe | ingredient_id | ingredient |
+-----------+-------------------------+---------------+------------+
| 1 | Macaroni & Cheese | 1 | Macaroni |
| 1 | Macaroni & Cheese | 2 | Cheese |
| 2 | Cheese on Toast | 2 | Cheese |
| 2 | Cheese on Toast | 4 | Toast |
| 3 | Beans on Toast | 3 | Beans |
| 3 | Beans on Toast | 4 | Toast |
| 4 | Cheese & Beans on Toast | 2 | Cheese |
| 4 | Cheese & Beans on Toast | 3 | Beans |
| 4 | Cheese & Beans on Toast | 4 | Toast |
| 5 | Toast & Jam | 4 | Toast |
| 5 | Toast & Jam | 5 | Jam |
| 6 | Humus | 6 | Chickpeas |
| 6 | Humus | 7 | Tahini |
+-----------+-------------------------+---------------+------------+
DELETE r
, ri
, i
FROM recipes r
JOIN recipe_ingredient ri
ON ri.recipe_id = r.recipe_id
JOIN ingredients i
ON i.ingredient_id = ri.ingredient_id
WHERE r.recipe = 'Humus';
SELECT * FROM recipes;
+-----------+-------------------------+
| recipe_id | recipe |
+-----------+-------------------------+
| 1 | Macaroni & Cheese |
| 2 | Cheese on Toast |
| 3 | Beans on Toast |
| 4 | Cheese & Beans on Toast |
| 5 | Toast & Jam |
+-----------+-------------------------+
SELECT * FROM ingredients;
+---------------+------------+
| ingredient_id | ingredient |
+---------------+------------+
| 1 | Macaroni |
| 2 | Cheese |
| 3 | Beans |
| 4 | Toast |
| 5 | Jam |
+---------------+------------+
在主表中设置层叠删除在主表中为每个表设置多个delete语句层叠删除在主表中如何设置？使用google或读取answerTag中的链接表示这是mysql。你的意思是创建4行？字符串SQL语句？你可以编写4个不同的查询或单个存储过程。如您所愿，这取决于您的应用程序，取决于您要执行的检查等etcstring sqlStatement=DELETE FROM Product、ProductStock、ProductSideImage、ProductImage，其中ProductID=@pid；如何联系关系？
SELECT * FROM recipes;
+-----------+-------------------------+
| recipe_id | recipe |
+-----------+-------------------------+
| 1 | Macaroni & Cheese |
| 2 | Cheese on Toast |
| 3 | Beans on Toast |
| 4 | Cheese & Beans on Toast |
| 5 | Toast & Jam |
| 6 | Humus |
+-----------+-------------------------+
SELECT * FROM ingredients;
+---------------+------------+
| ingredient_id | ingredient |
+---------------+------------+
| 1 | Macaroni |
| 2 | Cheese |
| 3 | Beans |
| 4 | Toast |
| 5 | Jam |
| 6 | Chickpeas |
| 7 | Tahini |
+---------------+------------+
SELECT r.*
, i.*
FROM recipes r
JOIN recipe_ingredient ri
ON ri.recipe_id = r.recipe_id
JOIN ingredients i
ON i.ingredient_id = ri.ingredient_id;
+-----------+-------------------------+---------------+------------+
| recipe_id | recipe | ingredient_id | ingredient |
+-----------+-------------------------+---------------+------------+
| 1 | Macaroni & Cheese | 1 | Macaroni |
| 1 | Macaroni & Cheese | 2 | Cheese |
| 2 | Cheese on Toast | 2 | Cheese |
| 2 | Cheese on Toast | 4 | Toast |
| 3 | Beans on Toast | 3 | Beans |
| 3 | Beans on Toast | 4 | Toast |
| 4 | Cheese & Beans on Toast | 2 | Cheese |
| 4 | Cheese & Beans on Toast | 3 | Beans |
| 4 | Cheese & Beans on Toast | 4 | Toast |
| 5 | Toast & Jam | 4 | Toast |
| 5 | Toast & Jam | 5 | Jam |
| 6 | Humus | 6 | Chickpeas |
| 6 | Humus | 7 | Tahini |
+-----------+-------------------------+---------------+------------+
DELETE r
, ri
, i
FROM recipes r
JOIN recipe_ingredient ri
ON ri.recipe_id = r.recipe_id
JOIN ingredients i
ON i.ingredient_id = ri.ingredient_id
WHERE r.recipe = 'Humus';
SELECT * FROM recipes;
+-----------+-------------------------+
| recipe_id | recipe |
+-----------+-------------------------+
| 1 | Macaroni & Cheese |
| 2 | Cheese on Toast |
| 3 | Beans on Toast |
| 4 | Cheese & Beans on Toast |
| 5 | Toast & Jam |
+-----------+-------------------------+
SELECT * FROM ingredients;
+---------------+------------+
| ingredient_id | ingredient |
+---------------+------------+
| 1 | Macaroni |
| 2 | Cheese |
| 3 | Beans |
| 4 | Toast |
| 5 | Jam |
+---------------+------------+