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LOGICAL DATA MODELLING AND SQL - Coursework Example
In order to define the data model, three (3) types of diagrams can be developed include: the conceptual data model, logical data model and physical data model. The conceptual…
In this case study of the SOUNMISSION Company, we have been given the conceptual diagram and we are required to form the logical Entity Relationship Diagram (ERD) based on the conceptual diagram. The logical data model is developed without considering the database tools to be used for creation and implementation of the database.
The logical ER data model facilitates to identify and specify additional data entities include but not limited to the Transactional and Operational data entities. Moreover, the logical ER data model contains more information related to the relationships, primary and foreign keys, as compared to the conceptual data model. In the ER logical models the attributes of the entities are defined, refined and categorized in diverse attribute types include: the derived attributes, composite attributes, multi-valued attributes, null and simple attributes. Furthermore, relationships are established in the logical ER data model. There are three (3) major types of the relationships include: one-one (1 to 1), one-many (1 to many) and many to many relationship. The relationships are based on the primary key and foreign key. The base table contains the primary key that makes a relationship with the other data type contains the foreign key. Usually, this type of relationship is said to be ‘one-to-many’ relationship. However, the same relationship can be changed by implementing constraint of uniqueness to the attribute / foreign key to restrict the duplicate values. This implies that the established relationship is one to one because both the data entities contain the non-duplicate value (Tao, n.d).
The document presents the conversion of the conceptual data model into the logical data model for the company named SOUNDMISSION. Moreover, the document can be considered as the base document for the development of the database for the company. In the beginning, it is required to identify the ...