Structuring Database for Accounting — Account STD 11 Commerce — Question

The following are the various categories of data models:

1. Relational Data Model: This data model is based on the relationship of collected data values. In this data model, data is organised into rows and columns. A row is regarded as a tuple, a column header is known as an attribute and the collective set of rows and columns, i.e. a table is called a relation. The table is known as a relation as it expresses the relationship between the rows and columns. This model provides the storage and retrieval functions and defines the data structure.

The relational data model was first introduced by Ted Codd in 1970 in a classic paper Codd, 1970. Prior to this, there were other data models which were proposed in sixties such as, hierarchical data model and network data model. These models are also known as legacy-models due to their large existing user-base.

2. Hierarchical Data Model: This data model mainly consists of records and parent-child relationships. While, a record is regarded as a collection of values that provides information regarding an entity or a relationship instance, on the other hand, a parent-child relationship explains the relationship between the parent record and children record type. In this data model, the records are organised in a tree structure rather than as an arbitrary graph. The data is represented by a collection of records and relationship among data is represented by links.
3. Network Data Model: This type of data model is sometimes also known as DBTG model, as the original network model was presented in CODASYL Data Base Task Group’s 1971, i.e. (DBTG). This data model basically consists of records and sets. While, data is stored in records, which consists of a group of related data values, on the other hand, sets describes the relationship between two records types. In this data model, data is also represented by collection of records and the relationship among data is represented by sets. This model provides many-to-many relationships in data.