文档介绍了MyBatis框架中的动态SQL功能，包括if、choose、foreach和where标签的使用方法，并通过示例展示了如何构建动态SQL查询。文档还提供了XML映射文件和Java代码示例，说明了如何在实际项目中应用这些动态SQL语句。

MyBatis 是一个开源的轻量级持久化框架，用于在 Java、.NET 和 Ruby on Rails 中自动化 SQL 数据库与对象之间的映射。它通过 XML 配置文件将 SQL 语句与应用逻辑解耦，简化了 JDBC 代码并提供了对存储过程和动态 SQL 的支持。MyBatis 的主要优势包括支持存储过程、内联 SQL、动态 SQL 以及提供类似 O/RM 工具的功能。与 Hibernate 等其他框架不同，MyBatis 强调使用原生 SQL，并通过 XML 配置实现高度的灵活性和可移植性。

Apache ShardingSphere is an open-source ecosystem providing distributed database solutions, including JDBC, Proxy, and Sidecar. It focuses on data sharding, distributed transactions, and governance. The document highlights the pluggable architecture introduced in version 5.x, enabling flexible embedding of features like data sharding and encryption. The system uses SPI (Service Provider Interface) for third-party implementations and supports various SQL dialects. It also provides a test engine for executing assertions without code changes.

The document provides a comprehensive guide to Apache ShardingSphere 5.1.1, detailing its features such as data scaling, encryption, sharding, and pluggable architecture. It outlines the processes for inventory, incremental, and switching phases in data scaling, using JDBC for data migration. Encryption is handled through SQL parsing and rewriting, supporting both plaintext and ciphertext storage. The management section covers metadata storage and dynamic orchestration of databases. Sharding functionality includes SQL processing steps and federation executor engine processes. The pluggable architecture is composed of three layers, enabling customization and extension of features without modifying kernel codes. The document also provides configuration details for ShardingSphere-JDBC, including Maven dependencies and data source creation, and explains resource operations, distributed databases, and DB discovery rules.

Apache ShardingSphere 5.0.0 is a Database Plus project that provides data sharding, distributed transaction, and distributed governance capabilities. It consists of three independent products: ShardingSphere-JDBC, ShardingSphere-Proxy, and ShardingSphere-Sidecar. The project focuses on reusing existing databases and their upper layers rather than creating new databases. Its core concepts include Link (flexible adaptation of database protocols and SQL dialects), Enhance (transparently providing additional features like sharding and encryption), and Pluggable (a micro-kernel architecture with three layers: L1 Kernel Layer for basic capabilities, L2 Feature Layer for enhanced features, and L3 Ecosystem Layer for database ecosystem integration). The pluggable architecture allows developers to customize their own systems like building blocks, enabling flexible feature embedding and component replacement.

文档详细介绍了Apache ShardingSphere 5.2.1的功能和配置，包括ShardingSphere-Proxy的配置手册、数据迁移解决方案、数据库协议兼容性、YAML配置方式以及分布式数据库的管理。ShardingSphere-Proxy支持通过YAML配置实现数据分片、读写分离、数据加密和影子库等功能，并与ShardingSphere-JDBC的配置保持一致。文档还提到ShardingSphere支持MySQL和PostgreSQL协议，能够自动转换SQL方言，并通过DistSQL进行配置管理。数据迁移功能自4.1.0版本起提供，适用于将单库数据迁移到分片数据库的场景，支持通过ZooKeeper进行集群模式配置。

Apache ShardingSphere 是一个数据库增强平台，旨在构建异构数据库之上的标准层和生态系统。它专注于现有数据库的扩展和增强，而非创建新的数据库。核心概念包括 Connect（灵活适配数据库协议和方言）、Enhance（透明提供额外功能，如分片、读写分离、数据加密等）和 Pluggable（通过微内核和三层插件模式实现灵活扩展）。文档介绍了其三个独立产品：ShardingSphere-JDBC、ShardingSphere-Proxy 和 ShardingSphere-Sidecar，并提供了配置、使用和扩展的详细说明。其目标是通过插件化架构帮助开发者灵活构建和定制自己的数据库系统。

Apache ShardingSphere 是一个开源生态系统，允许将任何数据库转换为分布式数据库系统。它包括 ShardingSphere-JDBC 和 ShardingSphere-Proxy，核心采用微内核和插件式架构。其设计理念是通过插件扩展功能，支持多源异构数据库，注重数据库的计算和存储能力的充分利用。文档介绍了其部署架构、快速入门指南、版本发布信息以及配置参数。插件式架构使其功能灵活扩展，支持数据分片、读写分离等多种特性。

Apache ShardingSphere 5.4.1 是一个功能强大的分布式数据库中间件，支持数据分片、分布式事务、读写分离等多种功能。其设计理念包括创建数据库上层标准、增强数据库计算能力以及构建数据库功能生态。它提供了两种运行模式：独立模式和集群模式，分别适用于不同的场景。文档还介绍了其插件式架构，支持多种数据库协议和功能扩展，适用于高可用性和高性能的应用场景。