Module 03 · Introducing Apache Cassandra: An Open-Source NoSQL Database

Glossary: Cassandra Basics术语表：Cassandra 基础

Welcome! This alphabetized glossary contains many of the terms you'll find within this course. This comprehensive glossary also includes additional industry-recognized terms not used in course videos. These terms are important for you to recognize when working in the industry, participating in user groups, and participating in other certificate programs.
欢迎！这个按字母顺序排列的术语表包含了您在本课程中会发现的大量术语。这个全面的术语表还包括了课程视频中未使用的、行业认可的术语。这些术语对于您在行业内工作、参与用户组以及参与其他认证项目时都非常重要。

Term 术语	Definition 定义
BSON	Binary JSON, or BSON, is a binary-encoded serialization format used for its efficient data storage and retrieval. BSON is similar to JSON but designed for compactness and speed. 二进制 JSON，或称 BSON，是一种用于高效数据存储和检索的二进制编码序列化格式。BSON 与 JSON 类似，但设计更为紧凑和快速。
Aggregation 聚合	Aggregation is the process of summarizing and computing data values. 聚合是指对数据值进行汇总和计算的过程。
Availability 可用性	In the context of CAP, availability means that the distributed system remains operational and responsive, even in the presence of failures or network partitions. Availability is a fundamental aspect of distributed systems. 在 CAP 理论中，可用性意味着分布式系统即使在存在故障或网络分区的情况下也能保持运行和响应。可用性是分布式系统的一个基本方面。
CAP	CAP is a theorem that highlights the trade-offs in distributed systems, including NoSQL databases. CAP theorem states that in the event of a network partition (P), a distributed system can choose to prioritize either consistency (C) or availability (A). Achieving both consistency and availability simultaneously during network partitions is challenging. CAP 是一个强调分布式系统（包括 NoSQL 数据库）中权衡的定理。CAP 定理指出，在网络分区（P）的情况下，分布式系统可以选择优先考虑一致性（C）或可用性（A）。在网络分区期间同时实现一致性和可用性是具有挑战性的。
Cluster 集群	A group of interconnected servers or nodes that work together to store and manage data in a NoSQL database, providing high availability and fault tolerance. 一组相互连接的服务器或节点，协同工作以在 NoSQL 数据库中存储和管理数据，提供高可用性和容错能力。
Clustering key 聚类键	A clustering key is a primary key component that determines the order of data within a partition. 聚类键是决定分区中数据顺序的主键组件。
Consistency 一致性	In the context of CAP, consistency refers to the guarantee that all nodes in a distributed system have the same data at the same time. 在 CAP 的背景下，一致性指的是保证分布式系统中的所有节点在同一时间拥有相同数据。
CQL	Cassandra Query Language, known as CQL, is a SQL-like language used for querying and managing data in Cassandra. Cassandra 查询语言，简称 CQL，是一种类似 SQL 的语言，用于查询和管理 Cassandra 中的数据。
CQL shell	The CQL shell is a command-line interface for interacting with Cassandra databases using the CQL language. CQL shell 是使用 CQL 语言与 Cassandra 数据库交互的命令行界面。
Decentralized 去中心化	Decentralized means there is no single point of control or failure. Data is distributed across multiple nodes or servers in a decentralized manner. 去中心化意味着没有单一的控制点或故障点。数据以去中心化的方式分布在多个节点或服务器上。
Dynamic table 动态表	A dynamic table allows flexibility in the columns that the database can hold. 一个动态表允许数据库在列上具有灵活性。
Joins 连接	Combining data from two or more database tables based on a related column between them. 基于它们之间相关列将两个或多个数据库表中的数据结合起来。
Keyspace 键空间	A keyspace in Cassandra is the highest-level organizational unit for data, similar to a database in traditional relational databases. 在 Cassandra 中，键空间是数据的最高级组织单元，类似于传统关系数据库中的数据库。
Partition Key 分区键	The partition key is a component of the primary key and determines how data is distributed across nodes in a cluster. 分区键是主键的一个组成部分，决定了数据如何在集群中的节点之间分布。
Partitions 分区	Partitions in Cassandra are the fundamental unit of data storage. Data is distributed across nodes and organized into partitions based on the partition key. 在 Cassandra 中，分区是数据存储的基本单元。数据会根据分区键分布在节点之间并组织成分区。
Peer-to-peer 点对点	The term peer-to-peer refers to the overall Cassandra architecture. In Cassandra, each node in the cluster has equal status and communicates directly with other nodes without relying on a central coordinator. If a primary node fails, another node automatically becomes the primary node. 对等网络是指 Cassandra 整体架构。在 Cassandra 中，集群中的每个节点具有同等地位，并直接与其他节点通信，而不依赖于中央协调器。如果主节点发生故障，另一个节点将自动成为主节点。
Primary key 主键	The primary key consists of one or more columns that uniquely identify rows in a table. The primary key includes a partition key and, optionally, clustering columns. 主键由一个或多个列组成，用于唯一标识表中的行。主键包括分区键，并且可选地包括聚簇列。
Replication 复制	Replication involves creating and maintaining copies of data on multiple nodes to ensure data availability, reduce data loss, fault tolerance (improve system resilience), and provide read scalability. 复制涉及在多个节点上创建和维护数据副本，以确保数据可用性、减少数据丢失、容错性（提高系统弹性）以及提供读扩展性。
Scalability 可扩展性	Scalability is the ability to add more nodes to the cluster to handle increased data and traffic. 可扩展性是指向集群中添加更多节点以处理增加的数据和流量。
Static table 静态表格	A static table has a fixed set of columns for each row. 静态表格的每一行都有固定的一组列。
Table 表格	A table is a collection of related data organized into rows and columns. 表格是将相关数据组织成行和列的集合。
Transactions 事务	Transactions are sequences of database operations (such as reading and writing data) that are treated as a single, indivisible unit. 事务是一系列数据库操作（如读取和写入数据），它们被视为一个单一、不可分割的单位。