sql - Records linked to any table? -

-

Hi Im with a little struggle and some ideas can be used ...

My The database has the following tables;

etc.

I would like to add "Notes" record to any type of record

Notes Table Notepell Intel (PK) Note: NITF Type Variant (3) NoteText Vartcha (100) Nodet DateTime

Where the note is a PK of a customer or Supplier etc. and Note type is that note is against the record of

Now I Realize that I can not add an FK Note that FK bin Many tables have to be present in all tables referring to.

How do you design above? Note: FK must be in any of the above tables

Cheers, Daniel

Accept this limitation that you can not teach the database about this foreign key constraint. So you have to do without integrity check (and cascading removal).

Your design is fine, it is easily extensible for extra tables, you can have multiple notes per unit, and the target tables do not even need to be aware of the note feature.

One advantage is that the separate table of table notes in this design is that you can easily run questions in all notes, for example "the most recent notes", or "any given information All the notes created by the user have been made "

that table is getting bigger for debate, dividing it into five tables will shrink the table into the fifth of its size, but this index-based access For someone Will not make the difference. Databases are prepared to handle large tables (as long as they are properly indexed).


Comments

Post a Comment

Popular posts from this blog

c# - ListView onScroll event -

-
I am programming a simple C # application, and I need a Scallow event on the list view. So I inherited the original ListView class created in ListviewEx witch. I found out how to locate the scroll message from WinAPI and I modified the WndProc method. Now I have this WndProc: protected override zero WndProc (Ref message message) {base.WndProc (Ref I); If (m.msg == WM_VSCROLL) {onScroll (This, New EventArgs ()); }} But the problem is, I do not know how to know about scrolling information. This data should be in wParam, but there is a LOWORD macro ++ like in C in C # and I switch to find the criteria like SB_ below, SB_ENDSCROLL, SB_PAGEUP etc. there any way Need to change the LOWORD macro from C #? Or any other way to find the necessary parameters about scrolling? You can define the WParam constants as the following: Private const int WM_HSCROLL = 0x114; Private Constant WM_VSCROLL = 0x115; Private contact int SBHOZZ = 0; Private Consultant SB_VERT = 1; Private Con...
Read more

PHP - get image from byte array -

-
I am trying to create a back-end for my mobile application. I am sending the content of an image in the body of the HTTP request (output stream) as a byte array, I want to read this stream of bytes in PHP scripts and take back an image. Can anyone tell me how can I do this? Thank you. You can obtain the request body $ body = Reading from file_get_contents ('php: // input'); What you do with that data Depending on you, you can write the data in a file as you mentioned that this is image data, you can drop the data into the object can do. Another option is to use and load the image.
Read more

Linux Terminal Problem with Non-Canonical Terminal I/O app -

-
I have a small app written in C to run on Linux. Part of the app accepts user-input from keyboard , And it uses non-canonical terminal mode so that it can respond to each keystroke. The section of the code that accepts input is a simple task that is called repeatedly in the loop: char get_input () {char C = 0; Int res = reading (input_tamille, & amp; c, 1); If (RSS == 0) 0 returns; If (res == -1) {/ * snip error handling * /} return c; } It reads a letter from the terminal if there is no input within a given time limit, (c_cc [VTIME] value in the vocabulary structure), read () 0 And get_input () is called again It all works very well, I have recently discovered that if you run this app in a terminal window, and then the app Close the terminal window without ending, the app will not exit Received, but CPU intensive launches into an infinite loop, where the read () returns 0 without waiting continued. So how can I get out of the apple if it runs from the terminal win...
Read more