Databases - The city where data living
As the name suggests, database is the bases where the series of data used for modeling some organization and its process are collected and stored into. Actually, there are operational databases and analytical databases in database management.
Operational databases
This type of databases is designed for collecting, modifying and maintaining the data in routines. As a result,. the data is dynamic and kept to be latest information. The simplest example is that the inventory database that keep updating and show the latest figures of inventory.
Analytical databases
It is designed for storing, querying, analyzing the data. This static data in a certain period of time is allowed to analyzed for performance review, decision making and forecasting the trend. The data is supposed to be hardly modified. The transaction databases is used for marketing analysis in some firms.
As we know, the databases are built in different variety of model that it is also called database model. Tow database models, hierarchical and network database model were commonly used before the relational databases.
Hierarchical database model
The model is constructed as the inverted tree. Each entity has only one-to-many relationship to another. For instance, a product are supplied by one or many vendors and purchased by one or many members. A member buy for one or many times. Based on the above, the model is constructed below:
There are explicit links between the tables. This design allows requester/administrator to retrieve the data rapidly. If a product is no longer sold, the records related this product in parent/child tables are also deleted. The problems usually occurs are that the entities under root tables could not be stored without the related root entity. In reality, member could exist even they have not purchased anythings. Still, it can solve by adding a dummy record into Product table first or separate the Member table from the databases such that member can be written in the tables of Member.
Network database model
This model are represented in forms of the nodes and set structures. Such design are competent to eliminate the inadequacy of hierarchical model and fast access the data by query. Nonetheless, Users are required to understand the set structures in the database.
Relational database model
The database model evolving with the time and technology. In order to tackle the data inconsistency and week integrity, relational database model born to be widely used until today.
The table structure consists of Keys, Attributes, Records and Relationship. Keys are classified as primary keys as well as foreign key. Former is unique identifier of each records. A table in relational database posses One and only one primary key. Later is a primary key of one table defines in another table. Attributes refer to the characteristics of entity such as name, age, birthday in Member table. Records is the row of tables, ie., the members: Alice, Brian, etc... The tables allows to have one-to-one,one-to-many or many-to-many relationship.
Additionally, This relational model could be visualized by ERD.
Entity-relationship diagram (ERD) is a type of data modeling to represent objects or concepts graphically within an information system or organization. It is aid to design the database schema logically.
Entity: a object/thing capable of an independent existence and can be uniquely identified.
Relationship: how entities are related to one another
Operational databases
This type of databases is designed for collecting, modifying and maintaining the data in routines. As a result,. the data is dynamic and kept to be latest information. The simplest example is that the inventory database that keep updating and show the latest figures of inventory.
Analytical databases
It is designed for storing, querying, analyzing the data. This static data in a certain period of time is allowed to analyzed for performance review, decision making and forecasting the trend. The data is supposed to be hardly modified. The transaction databases is used for marketing analysis in some firms.
As we know, the databases are built in different variety of model that it is also called database model. Tow database models, hierarchical and network database model were commonly used before the relational databases.
Hierarchical database model
The model is constructed as the inverted tree. Each entity has only one-to-many relationship to another. For instance, a product are supplied by one or many vendors and purchased by one or many members. A member buy for one or many times. Based on the above, the model is constructed below:
There are explicit links between the tables. This design allows requester/administrator to retrieve the data rapidly. If a product is no longer sold, the records related this product in parent/child tables are also deleted. The problems usually occurs are that the entities under root tables could not be stored without the related root entity. In reality, member could exist even they have not purchased anythings. Still, it can solve by adding a dummy record into Product table first or separate the Member table from the databases such that member can be written in the tables of Member.
Network database model
This model are represented in forms of the nodes and set structures. Such design are competent to eliminate the inadequacy of hierarchical model and fast access the data by query. Nonetheless, Users are required to understand the set structures in the database.
Relational database model
The database model evolving with the time and technology. In order to tackle the data inconsistency and week integrity, relational database model born to be widely used until today.
The table structure consists of Keys, Attributes, Records and Relationship. Keys are classified as primary keys as well as foreign key. Former is unique identifier of each records. A table in relational database posses One and only one primary key. Later is a primary key of one table defines in another table. Attributes refer to the characteristics of entity such as name, age, birthday in Member table. Records is the row of tables, ie., the members: Alice, Brian, etc... The tables allows to have one-to-one,one-to-many or many-to-many relationship.
Additionally, This relational model could be visualized by ERD.
Entity-relationship diagram (ERD) is a type of data modeling to represent objects or concepts graphically within an information system or organization. It is aid to design the database schema logically.
Entity: a object/thing capable of an independent existence and can be uniquely identified.
Relationship: how entities are related to one another
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