Apache Calcite Document

Apache Calcite 是一款开源SQL解析工具, 可以将各种SQL语句解析成抽象语法术AST(Abstract Syntax Tree), 之后通过操作AST就可以把SQL中所要表达的算法与关系体现在具体代码之中。Apache Calcite is a dynamic data management framework. It contains many of the pieces that comprise a typical database management system, but omits some key functions: storage of data, algorithms to process data, and a repository for storing metadata.