下列示例中，用于更新文档中内容的是( )
A: column.update_one({ "name": "Json" },{ "$set": { "alexa": "123" } }
B: column.update_many({ "name": { "$regex": "^F" } },{ "$set": { "alexa": "123" } })
C: result=column.find_one({"age":18})
D: result=column.insert_one({"age":18,"name":"Json"})
A: column.update_one({ "name": "Json" },{ "$set": { "alexa": "123" } }
B: column.update_many({ "name": { "$regex": "^F" } },{ "$set": { "alexa": "123" } })
C: result=column.find_one({"age":18})
D: result=column.insert_one({"age":18,"name":"Json"})
举一反三
- 下列是正确的Json格式对象的选项是: （ ） A: [name:”James”, age:18] B: [name=”James”, age=18] C: {name=”James”, age=18} D: {“name”:”James”, “age”:18}
- Which one of the followings columns has the highest column efficiency? A: packed column B: WCOT column C: SCOT column D: PLOT column
- Match Column A with Column B and give one example for each.
- 用下面的语句创建了Student表：CREATE TABLE Student(Sno CHAR(10) primary key,Sname VARCHAR(10),age SMALLINT,Cname VARCHAR(20) );请用ALTER TABLE语句设置age字段默认值为20，正确的语句是（）。 A: ALTER TABLE Student ALTER COLUMN age SET DEFAULT 20; B: ALTER TABLE Student CHANGE COLUMN age SET DEFAULT 20; C: ALTER TABLE Student ADD COLUMN age SET DEFAULT 20; D: ALTER TABLE Student DROP COLUMN age SET DEFAULT 20;
- Please match the words in column one the left side with the meaning in column two.