Organized, structured collections of data stored and accessed electronically, managed by database management systems to ensure efficient, secure, and reliable storage, retrieval, modification, and analysis of information.
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A set of properties (Atomicity, Consistency, Isolation, Durability) guaranteeing that database transactions are processed reliably, ensuring data integrity even in the event of errors or power failures. They are fundamental to transactional databases.
The process of creating copies of database data and transaction logs to ensure that the database can be restored to a consistent state after data loss, corruption, or system failure. It is crucial for data durability and business continuity.
A fundamental theorem in distributed computing stating that it is impossible for a distributed data store to simultaneously provide more than two out of three guarantees: Consistency, Availability, and Partition tolerance. It guides trade-offs in distributed system design.
A set of data values of a particular simple type, one for each row of the database table, representing a specific attribute or property of the entity described by the table. It defines the type of data stored.
A type of NoSQL database that stores data in column families, which are groups of columns that are frequently accessed together, allowing for high performance and scalability with sparse data. It's optimized for analytical queries over large datasets.
The management of simultaneous operations on a database to ensure that transactions are executed in a serializable manner, preventing data corruption and maintaining data consistency when multiple users access the same data. It uses mechanisms like locking.
The overall completeness, accuracy, and consistency of data throughout its entire lifecycle, ensuring that data is valid and reliable. It is maintained through various constraints and validation rules within the database.
An attribute that specifies the type of data that a column can hold, such as integers, text, dates, or boolean values, determining how the data is stored and manipulated. It ensures data consistency and validity.
A large, central repository that stores integrated data from one or more disparate sources, often optimized for analytical queries and reporting rather than transactional processing. It supports business intelligence activities.
A structured collection of data, typically stored electronically in a computer system, designed for efficient storage, retrieval, and management of information. It allows for organized access to data, making it easier to update, query, and manage.
Software that interacts with end-users, applications, and the database itself to capture and analyze data, providing an interface for managing and accessing the data efficiently. It handles data storage, retrieval, and security.
A situation in a database where two or more transactions are indefinitely waiting for each other to release the locks on resources that they need, resulting in a standstill where no transaction can proceed. It requires detection and resolution.
The process of intentionally adding redundant data to a database, often by combining tables, to improve query performance and simplify data retrieval, especially in data warehousing or reporting scenarios. It sacrifices some integrity for speed.
A type of NoSQL database that stores data in flexible, semi-structured document formats, typically JSON or BSON, allowing for rich, nested data structures without a predefined schema. It is ideal for rapidly changing data requirements.
A three-phase process used to integrate data from multiple sources into a data warehouse or another target system: Extracting data, Transforming it into a consistent format, and Loading it into the destination. It is crucial for data integration.
A column or a set of columns in one table that refers to the primary key in another table, establishing a link between the two tables and enforcing referential integrity. It ensures that relationships between data are valid.
A type of NoSQL database that uses graph structures for semantic queries with nodes, edges, and properties to represent and store data. It excels at modeling and querying complex relationships between data points.
A special lookup table that the database search engine can use to speed up data retrieval operations, similar to an index in a book. It stores a small copy of data from a table, sorted by the indexed columns.
A simple type of NoSQL database that stores data as a collection of key-value pairs, where each key is unique and directly maps to a specific data value. It offers high performance for simple read/write operations.
A mechanism used in concurrency control to prevent multiple transactions from accessing and modifying the same data simultaneously, thereby maintaining data integrity and consistency. It can be applied at different granularities (row, table).
A systematic process of organizing the columns and tables of a relational database to minimize data redundancy and improve data integrity, typically involving breaking down tables into smaller, related tables. It ensures data consistency.
A category of databases that provides a mechanism for storage and retrieval of data that is modeled in means other than the tabular relations used in relational databases, often designed for specific data models like key-value, document, or graph. They offer flexibility and horizontal scalability.
A column or a set of columns in a table that uniquely identifies each row in that table, ensuring data integrity and providing a way to reference individual records. It must contain unique values and cannot be NULL.
A request for data or information from a database, often expressed using a query language like SQL, which allows users to retrieve, manipulate, or update data based on specified criteria. It is the core mechanism for data interaction.
A type of database that stores and provides access to data points that are related to one another, organizing data into one or more tables (relations) of columns and rows. It uses SQL for data manipulation.
The process of maintaining multiple copies of data across different database servers, ensuring high availability, fault tolerance, and improved read performance by distributing queries. It keeps data synchronized across instances.
A single entry or record in a database table, representing a complete set of related data for a specific entity, where each value corresponds to a particular column (attribute). It uniquely identifies one instance of the entity.
The logical design or structure of an entire database, defining how the data is organized, including table names, column names, data types, relationships, and constraints. It acts as a blueprint for the database.
A method for horizontally partitioning data across multiple database instances or servers, where each shard (partition) holds a unique subset of the data. It improves scalability and performance for very large databases.
A standard language for managing and manipulating relational databases, used for querying data, defining schemas, and controlling access. It is the primary interface for interacting with most relational DBMS.
A prepared SQL code block or subroutine that is stored in the database and can be executed on demand, often encapsulating complex business logic. It improves performance, security, and reusability of database operations.
A collection of related data entries organized into rows and columns within a relational database, where each column represents an attribute and each row represents a unique record. It forms the basic structure for storing data.
A single logical unit of work performed on a database, comprising one or more operations (e.g., inserts, updates, deletes) that must be treated as an indivisible sequence. It either completes entirely or fails entirely, ensuring data consistency.
A special type of stored procedure that automatically executes or "fires" in response to certain events on a particular table or view, such as an INSERT, UPDATE, or DELETE operation. It enforces complex business rules.
A virtual table based on the result-set of a SQL query, whose content is defined by a query at the time it is accessed. It does not store data itself but rather displays data from one or more underlying tables.