theme: Databases title: Getting started with Databases for all
What are databases? They appear as spreadsheets that present data in rows and columns. If a database is relational then relationships can be created between them.Databases support complex querying because of its ability to create relationships between tables. They enforce consistency and data intergrity, avoiding duplication and ensuting data accuracy. Types of databases i) Centralized Database It is the type of database that stores data at a centralized database system. It comforts the users to access the stored data from different locations through several applications. These applications contain the authentication process to let users access data securely.it has decreased the risk of data management and It provides better data quality, which enables organizations to establish data standards.It is disadvantageous The size of the centralized database is large, which increases the response time for fetching the data and If any server failure occurs, entire data will be lost, which could be a huge loss. ii) Distributed Database In a distributed system, data is distributed among different database systems of an organization. These database systems are connected via communication links. Such links help the end-users to access the data easily. Distributed can be categorized as Homogeneous and Heterogenous Distributed database systems Homogenous DDB: These database systems execute on the same operating system and use the same application process and carry the same hardware devices. Heterogeneous DDB: These database systems execute on different operating systems under different application procedures, and carries different hardware devices. iii) Relational Database This database is based on the relational data model, which stores data in the form of rows(tuple) and columns(attributes), and together forms a table(relation).They use SQL for storing, manipulating, as well as maintaining the data. Properties of Relational Database A means Atomicity: This ensures the data operation will complete either with success or with failure. It follows the 'all or nothing' strategy. For example, a transaction will either be committed or will abort. C means Consistency: If we perform any operation over the data, its value before and after the operation should be preserved. For example, the account balance before and after the transaction should be correct, i.e., it should remain conserved. I means Isolation: There can be concurrent users for accessing data at the same time from the database. Thus, isolation between the data should remain isolated. For example, when multiple transactions occur at the same time, one transaction effects should not be visible to the other transactions in the database. D means Durability: It ensures that once it completes the operation and commits the data, data changes should remain permanent. iv) NoSQL Databases Non-SQL/Not Only SQL is a type of database that is used for storing a wide range of data sets. It is not a relational database as it stores data not only in tabular form but in several different ways. It came into existence when the demand for building modern applications increased. v)Cloud Database A type of database where data is stored in a virtual environment and executes over the cloud computing platform. It provides users with various cloud computing services (SaaS, PaaS, IaaS, etc.) for accessing the database. vi)Object-oriented Databases They use the object-based data model approach for storing data in the database system. The data is represented and stored as objects which are similar to the objects used in the object-oriented programming language. vii)Hierarchical Databases It is the type of database that stores data in the form of parent-children relationship nodes. Here, it organizes data in a tree-like structure. viii)Network Databases It is the database that typically follows the network data model. Here, the representation of data is in the form of nodes connected via links between them. it allows each record to have multiple children and parent nodes to form a generalized graph structure. ix)Personal Database Collecting and storing data on the user's system defines a Personal Database. x)Operational Database The type of database which creates and updates the database in real-time. It is basically designed for executing and handling the daily data operations in several businesses. xi)Enterprise Database Large organizations or enterprises use this database for managing a massive amount of data. It helps organizations to increase and improve their efficiency. xii)