Re: MySQL Foreign Key Issue

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*Question No. 01*
there are some kind of foreign key in database
Some of them want give any error when you delete from the table where the
foreign key is in, this cause the remove is "recursive" and it delete also
the ORDER linked to the CUSTOMER (CASCADE foreign key).
In other kind of foreign key (I don't remember the name) you cannot delete
CUSTOMER if there is some ORDER linked to them.

hope this will help

c-ya



2007/3/26, Lasitha Alawatta <Lasitha.A@xxxxxxxx>:

 Hello,



I have 2 issue, regarding MySQL "Foreign Key".

I have two tables;

Table 01 *CUSTOMER*

column name

characteristic

SID

Primary Key

Full_Name





Table *ORDERS*

column name

characteristic

Order_ID

Primary Key

Order_Date



Customer_SID

Foreign Key

Amount





When I run "ALTER TABLE ORDERS ADD FOREIGN KEY (customer_sid) REFERENCES
CUSTOMER(SID);" that sql statement,



I inserted 2 records to both tables.

* *

*Question No. 01.*

Then I removed 1 record from CUSTOMER table. But It want give any error
message. It should give an error message, because in ORDERS table already
have some records relevant to the deleted customer record in CUSTOMER table.



Question is why it want give any error ? (I'm using phpMyAdmin)



*Question No. 02.*

Is there any tool available for to get a Database diagram (like in MS SQL
Server). I found a tool call "DBDesigner 4". But it wants show the DB
Diagram.





Thanks in Advance,

Lasitha.







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