if not, then you are in for a suprise if yes, then tell me why is that happening? (DONT REMEMBER THE FOURTH ONE) The first one wont allow you to update the key when there is a dependant key, the second also does the same9almost), while the third one modifies the dependant foreign key also with the new value of your parent key.
i.e in a table of emp, consider, empno - integer, not null and primary key ename - char(20) esal - decimal(7,2) i can write a sql statment like, update emp set empno = empno 1 the above statment did execute succesfully and incremented all the values of empno by 1. bye, meetsrkhi meetsrk, its an easy thing to read the primary key and to add update with the existing and then again update the primary key. the thing is if you are updating the same key value then it will show the error. these options are declared when you are creating the child table.
Webcam tv sex free live - Updating primary key db2
There are four options on a primary key update when there is a foreign key defined on it: 1.
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CREATE TABLE country( name VARCHAR(100) NOT NULL, population BIGINT, PRIMARY KEY(name) ); CREATE TABLE city( name VARCHAR(100) NOT NULL, country VARCHAR(100) NOT NULL, PRIMARY KEY(name), FOREIGN KEY(country) REFERENCES country(name) ); And here is my problem: DB2 doesn't support "ON UPDATE CASCADE" and still referenced primary keys aren't allowed to change.
So how can I change a name of a country while it is still used by a city? CREATE TABLE country( id BIGINT, name VARCHAR(100) NOT NULL, population BIGINT, PRIMARY KEY(id) ); CREATE TABLE city( id BIGINT, name VARCHAR(100) NOT NULL, country_id BIGINT NOT NULL, PRIMARY KEY(id), FOREIGN KEY(country_id) REFERENCES country(id) ); I also thought about this solution, but is this really the only way?
CREATOR Regards, Tojy." id="ctl00_m_m_i_ctl00_gr_ctl07_bestanswerbody" class="textarea-bestanswerhidden" name="bestanswerbody" answerbody Id="268468" / 0 ORDER BY KEYSEQ ASC Foreign Key SELECT B.