Question

准备数据：

db.info.insert({contextInfo:"I am a student. I love learning. I am good at playing basketball and football. I love my family, I love my parents."})
db.info.insert({contextInfo:"I am a research and development engineer. I love working and studying. I love my family, I love my parents."})

建立全文索引

db.info.ensureIndex({contextInfo:'text'})

需要注意的是：这里使用 text 关键词来代表全文索引，就不建立数据模型了。

全文索引查找

建立好了全文索引，就可以查找了，查找时需要两个关键修饰符:

• $text：表示要在全文索引中查东西
• $search：后边跟查找的内容

> db.info.find({$text:{$search:"student"}})
{ "_id" : ObjectId("5cbb3105466a2bd461ae0f42"), "contextInfo" : "I am a student. I love learning. I am good at playing basketball and football. I love my family, I love my parents." }

查找多个词

全文索引支持多个词语查找，比如我们希望查找数据中有 student engineer learning 的数据（这是或的关系)，所以两条数据都会出现。

> db.info.find({$text:{$search:"student engineer learning"}})
{ "_id" : ObjectId("5cbb3107466a2bd461ae0f43"), "contextInfo" : "I am a research and development engineer. I love working and studying. I love my family, I love my parents." }
{ "_id" : ObjectId("5cbb3105466a2bd461ae0f42"), "contextInfo" : "I am a student. I love learning. I am good at playing basketball and football. I love my family, I love my parents." }

如果我们这时候希望不查找出来有 learning 这个单词的记录，我们可以使用 - 减号来取消。

db.info.find({$text:{$search:"student engineer -learning"}})

转义符：全文索引中是支持转义符的，比如我们想搜索的是两个词(love learning 和 development)，这时候需要使用 \ 斜杠来转义。

> db.info.find({$text:{$search:"\'love learning\' development"}})
{ "_id" : ObjectId("5cbb3107466a2bd461ae0f43"), "contextInfo" : "I am a research and development engineer. I love working and studying. I love my family, I love my parents." }
{ "_id" : ObjectId("5cbb3105466a2bd461ae0f42"), "contextInfo" : "I am a student. I love learning. I am good at playing basketball and football. I love my family, I love my parents." }

总结：全文索引在工作还是经常使用的，比如博客文章的搜索，长文件的关键词搜索，这些都需要使用全文索引来进行。