User:Malore/Wikidata structure/Item constraint

Types of item constraints

• single value constraint - members of the subject type shouldn't have more than one value for the object property
• multiple values constraint - members of the subject type shouldn't have more than one value for the object property

• EX: all instances/subclasses of cross-platform (Q174666) should have a platform (P400) property with multiple values.

• member requires statement

• EX: all instances/subclasses of quantum particle (Q28693603) should have a spin quantum number (P1122) property;
• EX: all instances/subclasses of Windows software (Q15593630) should have a operating system (P306) property with an instance/subclass of Microsoft Windows (Q1406) as value;

ADVANTAGES

• inherit properties from work to editions (how to do it?);
• substitute "union of";
• substitute "disjoint union of" with "one of constraint";
• distinguish primary items (e.g. software) from derived ones (e.g. Windows software is derived from subclass of (P279)Qsoftware (Q7397) and operating system (P306)Q1406{{{3}}}