Concept of Database Management System (DBMS)¶
A Database Management System (DBMS) is fundamentally a computer-based system designed for the efficient storage, retrieval, and management of data. It serves as a bridge between the user and the database, enabling various operations on the data contained within. These operations include data manipulation tasks such as inserting, updating, deleting, and querying data, as well as tasks related to the management of the database structure, such as defining schemas and creating or altering database tables.
DBMSs are crucial for ensuring that data is easily accessible, consistently organized, secure, and reliable. They are classified based on the types of data models they support, which dictate how data is structured within the database. The main types of DBMSs include relational DBMSs (RDBMS), which organize data into tables with defined relationships; non-relational or NoSQL DBMSs, which are designed for unstructured data and do not follow the table structure; and other models like hierarchical, network, and object-oriented DBMSs, each catering to specific data organization and access needs. This categorization helps in selecting the appropriate DBMS for specific application requirements, ensuring that the data storage and retrieval processes are optimized for the operational and analytical needs of businesses and organizations.
There are different types of database models :
1. hierarchical¶
In the hierarchical model, data is organized as tables or segments, which are structured in a hierarchy. This organization resembles a tree, where each record is linked to a single parent record and can have numerous child records. Though segments may form a linear sequence through logical links, these connections can also lead to a branched, or fan, structure with several offshoots. Such connections are referred to as directional associations. Within this structure, the segments that are designated by these logical links are known as child segments, while their counterparts are identified as parent segments. The segment at the very top of this hierarchy, which lacks a parent, is termed the root. Segments that do not have any child segments are known as leaves.
2. Network model¶
The Network Model extends the hierarchical data model by introducing a more flexible architecture. the Network Model allows for a more complex relationship where segments can have multiple parents. This is achieved by organizing the segments into various levels and establishing logical connections between segments across these levels. Typically, these connections enable many-to-many relationships among segments, which are represented as graphs. As a result, the rigid tree-like structure of the hierarchical model is replaced by a graph-like structure in the Network Model. This structure features a network of nodes (segments) interconnected by links (logical associations), allowing for a broader and more versatile way of representing relationships within the data.
3. Relational database management system¶
A relational database organizes data into a structured format, utilizing tables (or "relations") composed of columns and rows to store information. This arrangement facilitates a clear understanding of how various data entities are interconnected. The connections between tables, known as relationships, are formed based on the interactions among the tables, allowing for an organized and logical grouping of data.
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