MySQL Foreign Key Issue

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. DOTW DISCLAIMER: This e-mail and any attachments are strictly confidential and intended for the addressee only. If you are not the named addressee you must not disclose, copy or take any action in reliance of this transmission and you should notify us as soon as possible. If you have received it in error, please contact the message sender immediately. This e-mail and any attachments are believed to be free from viruses but it is your responsibility to carry out all necessary virus checks and DOTW accepts no liability in connection therewith. This e-mail and all other electronic (including voice) communications from the sender's company are for informational purposes only. No such communication is intended by the sender to constitute either an electronic record or an electronic signature or to constitute any agreement by the sender to conduct a transaction by electronic means.