#Erwin data model interview questions software

Dept_No has to be connected to EMPLOYEE table and Dept_No in EMPLOYEE table is a foreign key to DEPARTMENT table. Employee_No has one to many relationship with Department_No because one or more employees can work in the same department. So DEPARTMENT table should be created and Dept_No should be the primary key of the DEPARTMENT table.We have to create EMPLOYEE table and Employee_No should be the primary key of the table and later other stand alone columns and foreign key columns have to be added based on the relationship.One employee can work in one or more projects and one project can have one or more employees.įollowing sections, how business requirements are transformed to a data model.Īnalysis: How many tables should be present in the data model?.One or more employees can have the same title.One employee can work in only one department and one or more employees can work in the same department.Manager Numbers are also Employee Numbers.One employee has only one manager and CEO doesn’t have any manager.Sample Data:ĭata Modeler analyzes data, talks to business analysts or smart management experts in the client and understands the requirements.įollowing section describes business requirements.

#Erwin data model interview questions software

Assume that the client has sent the following information to the software company and software company has to create logical and physical data models and implement that in a database. Let us consider a software company, which is involved in implementing projects. If more than one column is present as a primary key, then it is called as primary key.

Foreign Key:Īttributes within same entity or attributes from different entities will be connected by a connector (foreign key) to the primary key attribute. If the attribute (column) has to be unique and should contain NON-NULL values, data modelers create primary key constraint on that particular attribute and it is called the primary key attribute of that entity. With the following example, we will explain you about how you can learn and practice different types of relationships with Quest’s TOAD Software tool. Occasionally, there may arise a situation where you need to create a foreign key column by connecting a relationship to primary key column of the same table, which is called as self-referential or recursive relationship. Based on cardinality, relationship are broadly classified into one to one relationship, one to many relationship and many to many relationship. Identifying relationship and Non-Identifying relationship are two types of relationships. Usually in a data model, Tables (Entities) looks like rectangular or square type boxes, which contains columns(attributes) and these tables are connected by lines (relationships). Analysis of Data and creating Tables & Relationships: