oracle9i中的集合运算.(索引，嵌套表，变长数组)-oracle9i of set operations. (Indexing, nested table, variable-length arrays)

R树索引树的代码,用于空间数据库索引，是先进比较流行的数据库索引算法-R-tree index tree code, the index for spatial databases, advanced database indexing algorithm more popular

Oracle学习参考，包括ROWID的概念、索引的概念、唯一索引、组合索引、位图索引和 基于函数的索引等。 -Oracle Learning Resources, including the ROWID of the concept, the concept of indexing, unique indexes, composite indexes, bitmap indexes and function-based indexes.