1st Normal Form

An entity is said to be in the 1st Normal Form when it contains "No repeating data." If all of the attributes in the entity can contain one and only one value, the entity is said to be in the 1st Normal Form. Repeating data are attributes that can have more than one value in an entity and don't belong there. They belong in some other entity.

The Data Analyst analyzes the attributes in each entity and asks, "If I assign this attribute to this entity, will it contain only one value?" If the answer is "No", the analyst moves the repeating attribute to another entity or a new entity. If new, the analyst assigns a name to the new entity. The name should describe the data contained in the new entity. The analyst also creates a meaningful identifier for the new entity.

Words

    Purchase Order -- data occurs once
            Id; Number; Date; Status; Approved By; Requested By; DeliveryDate; Notes;
            Office.Id; Supplier.Id; Total

    Company -- data occurs once
            Id; Name

    Office -- data occurs once
            Id; Name; Street; Suite; City; State; ZipCode; Country; Phone; Attention;
            Company.Id

    OfficeDepartment -- data occurs once
            Office.Id; Department.Id;

    Supplier -- data occurs once
            Id; Name; Street; Suite; City; State; ZipCode; Country; Terms; Phone; Email

    PurchaseOrderEmployee -- data occurs once
            PurchaseOrder.Id; Employee.Id; Role

    Employee -- data occurs once
            Id; Name; Phone

    DepartmentEmployee -- data occurs once
            Department.Id; Employee.Id; Title

    Department -- data occurs once
           Id; Name

    Item -- data occurs once
           Id; Code; Name; Quantity; Price; Discount; Total; PurchaseOrder.Id

Words