what is a one to one relationship in a database
One-to-one (data model) In a relational database, a one-to-one relationship exists when one row in a table may be linked with only one row in another table and vice versa. It is important to note that a one-to-one relationship is not a property of the data, but rather of the relationship itself. A list of mothers and their children may happen to describe mothers with only one child, in which case one row of the mothers table will refer to only one row of the children table and vice versa, but the relationship itself is not one-to-one, because mothers may have more than one child, thus forming a one-to-many relationship.
Committed relationship A committed relationship is an interpersonal relationship based upon a mutually agreed-upon commitment to one another involving love, trust, honesty, openness, or some other agreed-upon behavior. Forms of committed relationships are: close friendship, long-term relationships (LTR), engagement, marriage, and civil unions. The term is most commonly used with informal relationships, such as "going steady," but may encompass any relationship where an expressed commitment is involved.