Cardinality

[Former Member]

Hi,

From F4 help i got the following:

<i><b>Cardinality of a relationship</b>

The cardinality (n : m) describes the foreign key relationship with regard to the number of possible dependent records involved (records of the foreign key table) or referred records (records of the check table).

<b>The right side of the cardinality has the following significance:</b>

• m = 1

For each record of the check table there is exactly one dependent record.

• m = C

For each record of the check table there is at most one dependent record.

• m = N

For each record of the check table there is at least one dependent record.

• m = CN

For each record of the check table there are any number of dependent records.</i>

I am not able to understand the above description. Specially what is dependent records. Can any one make me understand what is cardinality if possible with example.

Thanks in advance.

abhishek

[Former Member]

suppose the left side is you and the right side are aspects of you

1:1 could be the the relation ship you have with birth dates(<u>is born on</u>). you only have 1 birthdate

1:n could be the relationship with the number of languages you can speak, this is always 1, namely your mother language but can be more than one.

0:1 this could be in a (monogamistic society) the relationship married to. This can be 0 or 1 but not more

0:n could be the relationship <u>is divorced with</u>, this can be 0 or more.

hope this clarifies it a bit.

Kind regards, Rob Dielemans

[Former Member]

hi

good

go throgh this links

http://help.sap.com/saphelp_nw04/helpdata/en/b2/fbb859c64611d295dd00a0c929b3c3/content.htm

http://help.sap.com/saphelp_nw04/helpdata/en/a7/d50f395fc8cb7fe10000000a11402f/content.htm

reward point if helpful.

thanks

mrutyun^

[Former Member]

Hi,

• m = 1 1X1 (Minimum 1 record must exists)

For each record of the check table there is exactly one dependent records of the foreign key table.

• m = C 1XC (At most 1 record exists)

For each record of the check table there is at most one dependent records of the foreign key table.

• m = N 1XN (At least 1 & more records exists)

For each record of the check table there is at least one dependent records of the foreign key table.

• m = CN 1XCN (1 or more records exists)

For each record of the check table there are any number of dependent records of the foreign key table.

Bye,

KC