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Home -> Community -> Mailing Lists -> Oracle-L -> RE: flag
Y/Null instead of Y/N worked really well for us. We had a multi-million row table that was often queried with the flag value and only returned a small number of rows based on the flag. An index was needed on the flag but if all rows contained a 'Y' or an 'N' then the index required a lot of overhead and quickly became stale and needed rebuilding. By changing the data to Y/Null instead of Y/N and rewriting the code just a little we had a much smaller index and performance didn't degrade. Using NULL for boolean operations works well because NULL is not nothin' ya know.
-----Original Message-----
Sent: Wednesday, May 21, 2003 9:07 PM
To: Multiple recipients of list ORACLE-L
I liked the idea of using 0/1 for Java Boolean operations but on the other side of the argument is that we inadvertently did a datatype transformation and ended up not using the index (Oracle implicitly converted the data side to number and failed to use the index, where we compared against a field defined, based on a table and the table had been created with wrong data type AAAaaargh.
I much prefer Y/N. However because many of our applications (for Fed Govt) need to be bilingual, 1/0 is used (rather than worry about storing Oui/Non)
If it's a Y/N flag (boolean) that needs to be indexed then you can just make it Y/NULL and handle it via code. This can substantially reduce the size of the index. (not talking about bitmap indexes now)
-----Original Message-----
Sent: Wednesday, May 21, 2003 3:48 PM
To: Multiple recipients of list ORACLE-L
Are you planning to use the flagged column as a boolean across a jdbc connection? If so, then go with a number datatype. The 9i jdbc driver does not know how to handle boolean datatype, thus if you store 'Y' in a char column the jdbc driver will throw errors when the java application calls GetBoolean against the jdbc driver.
Mark
-----Original Message-----
Sent: Wednesday, May 21, 2003 1:17 PM
To: Multiple recipients of list ORACLE-L
Would you use a number or char for a flag in a table? Would you use a char since it's one byte and a number is 22 bytes?
Dave
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