图数据库全文索引

图数据库全文索引（Full-Text Indexing）是指在图数据库中实现对文本类型属性的全文搜索。相较于其他类型数据库的全文搜索，它能更高效、精确地检索图节点和其属性，因为它能以节点为中心，搜索整个图数据库中与之相连的节点，并按照文本相似度进行排序。

在传统关系型数据库中，支持全文搜索的SQL语句需要使用LIKE和%等模糊查询符号，这样的搜索效率比较低，并且只能搜索少量文本内容。另外它也支持在文本属性中采用Lucene、Solr等独立搜索引擎实现全文索引。

在图数据库中实现全文索引，需要考虑以下几个方面：

1.支持全文搜索的文本类型属性集成到图模型中，以便可以用于数据搜索。

2.借助权重类算法（TF-IDF、BM25等）计算搜索词在所有节点中的权重得分，从而按照相关性对节点进行排序。

3.在大型图数据集上进行全文搜索时，需要协调分散的搜索请求，最大化利用硬件资源。

以下为Neo4j图数据库实现全文搜索示例代码：

创建图数据库模型：

CREATE (book:Book {title:"The Lord of the Rings", author:"J.R.R. Tolkien", year:"1954", text:"In a hole in the ground there lived a hobbit."})
CREATE (book:Book {title:"To Kill a Mockingbird", author:"Harper Lee", year:"1960", text:"When he was nearly thirteen, my brother Jem got his arm badly broken at the elbow."})
CREATE (book:Book {title:"Harry Potter and the Philosopher's Stone", author:"J.K. Rowling", year:"1997", text:"Mr. and Mrs. Dursley, of number four, Privet Drive, were proud to say that they were perfectly normal, thank you very much."})
CREATE (book:Book {title:"1984", author:"George Orwell", year:"1949", text:"It was a bright cold day in April, and the clocks were striking thirteen."})
CREATE (book:Book {title:"Pride and Prejudice", author:"Jane Austen", year:"1813", text:"It is a truth universally acknowledged, that a single man in possession of a good fortune, must be in want of a wife."})