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On 04/08/2014 03:26 PM, CS_DBA wrote:
On 04/08/2014 03:17 PM, Rob Sargent
wrote:
On 04/08/2014 03:09 PM, CS_DBA
wrote:
On 04/08/2014 02:58 PM, Rob
Sargent wrote:
On 04/08/2014 02:51 PM, CS_DBA
wrote:
Hi All
we have a table like so:
customer (
cust_id integer not null primary key,
cust_group_id integer not null,
group_account_id integer not null,
cust_name varchar not null,
...
)
we want to force the cust_group_id to be unique across all
group_account_id's but not necessarily across the entire
table
I assume the best approach would be a check constraint
yes? Will this be excessively poor per performance if the
table gets big?
Thoughts?
Thanks in advance
A
unique index on cust_group_id and group_account_id
doesn't do it for you?
oh
right! duh! It's been one of those days....
Which
column goes first depends on your lookup expectations.
Thanks!
Here's another one:
customer (
cust_id integer not null primary key,
cust_group_id integer not null,
group_account_id integer not null,
cust_name varchar not null,
cust_template_id integer,
...
)
If cust_template_id IS NOT NULL then it must reference a valid
cust_id
Check constraint?
Nope.
Useless column :). You already have cust_id so cust_template_id
is either null or already known.
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