c# - Recursively checking for a duplicate random number in a database -

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i create random number , check if exists in database table. if does, generate 1 , check again, following work?

public int generatenumber() {     random r = new random();     int num = r.next(1000);      //psuedo-code     if(num in table)         generatenumber();      return num; }

it seems based on answers below recursion should avoided here , should auto-increment number, alternative either start auto-increment @ 1 , pad 0's until is 8 characters long or start @ 10,000,000.

also, if datatype has varchar(8). how can auto-increment number, store in in varchar(8)?

this not problem needs solved recursion. not mention fact if have fair few numbers in database, , loops lots of times, you'll stack overflow error. why not change iterative function:

public int generatenumber() {     random r = new randon();     int num = r.next(1000);      while(num in database)     {         num = r.next(1000);     }      return num; }

different approach, while i'm here

why not implement transitive difference between these values? i.e: first number one, 2 etc. need recent entry, , add 1 it. no need consistently keep making database queries.


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