Ideas on how to explain a one-to-of several or…
For the a one-to-one matchmaking, a row inside desk A might www.datingranking.net/cs/blackplanet-recenze/ do not have several matching row for the table B, and you will vice versa. A single-to-you to definitely relationships is made if the each of brand new relevant columns was first important factors otherwise features unique constraints.
This relationships is not common, since most recommendations that’s related in this manner could be in a single dining table. You might use a-one-to-one relationship to take the adopting the measures:
- Split a dining table with many columns.
- Divide part of a dining table having defense reasons.
- Shop research that’s brief-resided and may even be easily erased because of the removing the table.
- Store suggestions one to applies just to an excellent subset of one’s chief table.
Inside Supply, the primary trick side of a one-to-you to definitely relationships is denoted by a key symbol. The newest overseas secret front is also denoted of the a button symbol.
How exactly to describe dating anywhere between dining tables
When you carry out a relationship anywhere between tables, the fresh new associated sphere do not have to have a similar names. However, associated industries need to have the same analysis kind of unless of course an important secret community are an AutoNumber job. You could potentially suits a keen AutoNumber community with several field merely in the event that theFieldSizeproperty from each of this new coordinating fields is the same. Including, you can suits a keen AutoNumber career and you will a variety profession if theFieldSizeproperty of each other industries isLong Integer. Regardless of if each other coordinating sphere is Amount fields, they have to have the sameFieldSizeproperty function.
- Push F11 to alter on the Database screen.
- With the Gadgets selection, simply click Dating. Leer más «Ideas on how to explain a one-to-of several or one-to-you to definitely relationship»