When it comes to interviews for adult developers, database questions can be a major part of the conversation. It is important to be prepared to answer questions about database design, database administration, and database security. Here are some of the most common database interview questions and answers that adult developers should be prepared to answer.
A database is a structured collection of data, usually stored in a computer system. It is organized in such a way that it can easily be accessed, managed, and updated. Databases are used to store information such as customer records, employee records, financial records, and more.
Database design is the process of designing a database to meet the needs of an organization. This includes creating a logical structure for the data, defining the relationships between the data, and creating a physical structure for the data. It also involves designing the user interface, security, and other aspects of the database.
Database administration is the process of managing and maintaining a database. This includes tasks such as creating and modifying databases, setting up user accounts, backing up data, and more. Database administrators are responsible for ensuring the security, performance, and availability of a database.
Database security is the process of protecting a database from unauthorized access, modification, or destruction. This includes implementing access control measures such as authentication, authorization, and encryption. It also involves monitoring the database for suspicious activity and responding to security incidents.
SQL (Structured Query Language) is a programming language used to interact with databases. It is used to create, modify, and query databases. SQL is used to retrieve data from databases, insert new data into databases, and update existing data in databases.
A relational database is a type of database that stores data in related tables. The tables are linked together through relationships, which are defined by common fields between the tables. This allows for data to be retrieved from multiple tables in a single query.
A NoSQL database is a type of database that does not use the relational model. Instead, it stores data in a non-relational way, such as in documents, key-value pairs, or graphs. NoSQL databases are often used for web applications and other applications that require flexibility and scalability.
Data normalization is the process of organizing data in a database to reduce redundancy and improve data integrity. This includes removing duplicate data, minimizing the number of null values, and ensuring that data is stored in the most efficient way possible.
Indexing is the process of creating an index for a database. An index is a data structure that stores the values of a column in a table in a specific order. This allows for faster retrieval of data from the database.
A transaction is a set of operations that are performed on a database. Transactions are used to ensure that a set of operations are performed in an atomic manner, meaning that either all of the operations are performed, or none of them are. This ensures the integrity of the data in the database.
ACID (Atomicity, Consistency, Isolation, and Durability) is a set of properties that describe the behavior of a transaction. Atomicity ensures that either all of the operations in a transaction are performed, or none of them are. Consistency ensures that the data in the database remains valid after a transaction is completed. Isolation ensures that concurrent transactions do not interfere with each other. Durability ensures that the data in the database remains intact even in the event of a system failure.