Waynn Lue wrote:
As a side note, FKs do enforce other table specific properties like
indexes on the fields being constrained, so they do add value there as
well. But there's of course an extra cost on updates and inserts to
see if the FK is violated.
On the external table? No they don't.
At 4:25 PM -0500 12/11/08, Robert Cummings wrote:
On Thu, 2008-12-11 at 16:24 -0500, Robert Cummings wrote:
lock table
check enrolment count
no room
unlock table
generate error
have room
insert row
unlock table
Ba da boom.
I should
Hi gang:
I know this is a MySQL question, but I get a better reply from this
group than the MySQL list (no offense meant to that list) -- In any
event, here goes.
I currently have a project that's a classic example of a relational
database, namely the course, student, and instructor
On Thu, Dec 11, 2008 at 12:56 PM, tedd tedd.sperl...@gmail.com wrote:
Hi gang:
I know this is a MySQL question, but I get a better reply from this group
than the MySQL list (no offense meant to that list) -- In any event, here
goes.
I currently have a project that's a classic example of a
Hey tedd ---
Do I understand your structure correctly that you have something like:
Courses (table)
course_id,
subject_id,
student1_id,
student2_id,
student3_id,
student4_id,
etc.
Is that right?
Ken
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At 12:29 PM -0600 12/11/08, phphelp -- kbk wrote:
Hey tedd ---
Do I understand your structure correctly that you have something like:
Courses (table)
course_id,
subject_id,
student1_id,
student2_id,
student3_id,
student4_id,
etc.
Is that right?
Ken
Ken:
That was right, but I think I've
On Thu, 2008-12-11 at 13:27 -0500, Bastien Koert wrote:
On Thu, Dec 11, 2008 at 12:56 PM, tedd tedd.sperl...@gmail.com
I believe I can create the Course table (excluding everything not germane)
like so:
INDEX (student_id),
FOREIGN KEY (student_id)
REFERENCES (students(id)),
At 1:48 PM -0500 12/11/08, Robert Cummings wrote:
On Thu, 2008-12-11 at 13:27 -0500, Bastien Koert wrote:
On Thu, Dec 11, 2008 at 12:56 PM, tedd tedd.sperl...@gmail.com
Does anyone have any example code to show me the actual syntax?
Joins should allow you to pull the data from the table
On Thu, 2008-12-11 at 13:46 -0500, tedd wrote:
At 12:29 PM -0600 12/11/08, phphelp -- kbk wrote:
Hey tedd ---
Do I understand your structure correctly that you have something like:
Courses (table)
course_id,
subject_id,
student1_id,
student2_id,
student3_id,
student4_id,
etc.
Is
On Dec 11, 2008, at 12:55 PM, Robert Cummings wrote:
On Thu, 2008-12-11 at 13:46 -0500, tedd wrote:
At 12:29 PM -0600 12/11/08, phphelp -- kbk wrote:
Hey tedd ---
Do I understand your structure correctly that you have something
like:
Courses (table)
course_id,
subject_id,
On Thu, 2008-12-11 at 13:56 -0500, tedd wrote:
At 1:48 PM -0500 12/11/08, Robert Cummings wrote:
On Thu, 2008-12-11 at 13:27 -0500, Bastien Koert wrote:
On Thu, Dec 11, 2008 at 12:56 PM, tedd tedd.sperl...@gmail.com
Does anyone have any example code to show me the actual syntax?
At 1:55 PM -0500 12/11/08, Robert Cummings wrote:
Student attendance should be a table with rows for each student in
attendance. If you want to limit the number make a check before adding
another student. Don't hard code the number via fields like above or
you'll find it overly ugly to
On Thu, Dec 11, 2008 at 2:32 PM, tedd tedd.sperl...@gmail.com wrote:
At 1:55 PM -0500 12/11/08, Robert Cummings wrote:
Student attendance should be a table with rows for each student in
attendance. If you want to limit the number make a check before adding
another student. Don't hard code the
At 3:14 PM -0500 12/11/08, Andrew Ballard wrote:
That's the way to go. Just keep in mind that you will have to consider
ways of preventing overloading your courses due to concurrency,
whether you use table locks or devise your own mechanism. I don't know
if you are allowing students to
On Thu, 2008-12-11 at 16:17 -0500, tedd wrote:
At 3:14 PM -0500 12/11/08, Andrew Ballard wrote:
That's the way to go. Just keep in mind that you will have to consider
ways of preventing overloading your courses due to concurrency,
whether you use table locks or devise your own mechanism. I
On Thu, 2008-12-11 at 16:24 -0500, Robert Cummings wrote:
On Thu, 2008-12-11 at 16:17 -0500, tedd wrote:
At 3:14 PM -0500 12/11/08, Andrew Ballard wrote:
That's the way to go. Just keep in mind that you will have to consider
ways of preventing overloading your courses due to concurrency,
As a side note, FKs do enforce other table specific properties like
indexes on the fields being constrained, so they do add value there as
well. But there's of course an extra cost on updates and inserts to
see if the FK is violated.
Waynn
On 12/11/08, Colin Guthrie gm...@colin.guthr.ie wrote:
Waynn Lue wrote:
As a side note, FKs do enforce other table specific properties like
indexes on the fields being constrained, so they do add value there as
well. But there's of course an extra cost on updates and inserts to
see if the FK is violated.
On the external table? No they don't.
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