topic Re: Cardinality in Application Development and Automation Discussions

Cardinality

Former Member — Wed, 07 Nov 2007 15:01:42 GMT

Hi,

From F4 help i got the following:

Cardinality of a relationship

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).

The right side of the cardinality has the following significance:

• 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 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

Re: Cardinality

Former Member — Wed, 07 Nov 2007 15:22:31 GMT

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(is born on). 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 is divorced with, this can be 0 or more.

hope this clarifies it a bit.

Kind regards, Rob Dielemans

Re: Cardinality

Former Member — Wed, 07 Nov 2007 15:39:15 GMT

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^

Re: Cardinality

Former Member — Wed, 07 Nov 2007 15:49:48 GMT

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,