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Normalization organizes database tables to reduce redundancy.
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A Database is an organized collection of structured data stored electronically in a computer system. It allows easy access, management, and updating of data. Databases are essential in modern applications like banking systems, e-commerce websites, hospital records, and social media platforms. Common database types include Relational (SQL) and Non-Relational (NoSQL) databases.
SQL databases are relational, store data in structured tables with fixed schema, and use SQL for queries. Examples: MySQL, PostgreSQL, Oracle. NoSQL databases are non-relational, store data in flexible formats like documents, key-value pairs, or graphs. Examples: MongoDB, Redis, Cassandra. SQL is better for complex queries; NoSQL is better for large-scale unstructured data.
ACID properties ensure reliable database transactions: Atomicity (transaction is all-or-nothing), Consistency (database remains in a valid state), Isolation (concurrent transactions do not interfere), and Durability (committed transactions are permanently saved). These properties are critical in banking and financial applications where data integrity is essential.
A Primary Key uniquely identifies each record in a table and cannot be NULL or duplicate. A Foreign Key is a field in one table that refers to the Primary Key in another table, creating a relationship between tables. For example, in a student database, StudentID is the Primary Key in the Students table and a Foreign Key in the Marks table.
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