本文介绍，在巨杉SequoiaDB 5上做最简单的增删改查操作的例子。
目录导航
创建CS
[sdbadmin@gbase_rh7_001 ~]$ sdb
Welcome to SequoiaDB shell!
help() for help, Ctrl+c or quit to exit
> var db=new Sdb()
Takes 0.011562s.
> var cs=db.createCS('emp')
Takes 0.008918s.
创建CL
> db.emp.createCL("employees")
localhost:11810.emp.employees
Takes 0.316113s.插入数据
通过insert
注意2行数据，name是和第1行数据相，但多了birth数据。
> db.emp.employees.insert({id:1,name:"First"})
{
"InsertedNum": 1,
"DuplicatedNum": 0
}
Takes 0.003210s.
> db.emp.employees.insert({id:2,name:"First",birth:"1990-12-13"})
{
"InsertedNum": 1,
"DuplicatedNum": 0
}
Takes 0.001932s.
通过execUpdate的SQL格式
insert into () values ()
> db.execUpdate("insert into emp.employees (id,name) values(3,'second')");
{
"InsertedNum": 1,
"DuplicatedNum": 0
}
Takes 0.019914s.
> db.exec("select * from emp.employees where id='3'");
Return 0 row(s).
Takes 0.001557s.
> db.exec("select * from emp.employees where id=3");
{
"_id": {
"$oid": "5ffee5c77606f131940aa9e3"
},
"id": 3,
"name": "second"
}
Return 1 row(s).
Takes 0.001759s.
>
查询
全表查询
> db.exec('select * from emp.employees');
{
"_id": {
"$oid": "5ffef97795d25e56d34d79d7"
},
"id": 1,
"name": "First"
}
{
"_id": {
"$oid": "5ffef9e295d25e56d34d79d8"
},
"id": 2,
"name": "First",
"birth": "1990-12-13"
}
Return 2 row(s).
Takes 0.003467s.
带条件查询
注意条件是有类型的，比如=1是数字，=’1‘是字符串，结果不一定相等。
> db.exec('select * from emp.employees where id=1');
{
"_id": {
"$oid": "5ffef97795d25e56d34d79d7"
},
"id": 1,
"name": "First"
}
Return 1 row(s).
Takes 0.002669s.
> db.exec('select * from emp.employees where name="First"');
{
"_id": {
"$oid": "5ffef97795d25e56d34d79d7"
},
"id": 1,
"name": "First"
}
{
"_id": {
"$oid": "5ffef9e295d25e56d34d79d8"
},
"id": 2,
"name": "First",
"birth": "1990-12-13"
}
Return 2 row(s).
Takes 0.002355s.
>
查询唯一的id
> db.emp.employees.find({id:1})
{
"_id": {
"$oid": "5ffef97795d25e56d34d79d7"
},
"id": 1,
"name": "First"
}
Return 1 row(s).
Takes 0.001672s.查询有重复的Name
> db.emp.employees.find({name:"First"})
{
"_id": {
"$oid": "5ffef97795d25e56d34d79d7"
},
"id": 1,
"name": "First"
}
{
"_id": {
"$oid": "5ffef9e295d25e56d34d79d8"
},
"id": 2,
"name": "First",
"birth": "1990-12-13"
}
Return 2 row(s).
Takes 0.001782s.
更新
更新操作本身，是可以增加额外属性的，等同于增加了字段。
如下update时给id=3的记录增加了birth字段，在前面insert into时是没有的。
> db.execUpdate("update emp.employees set birth='2020-12-13' where id=3");
{
"UpdatedNum": 1,
"ModifiedNum": 1,
"InsertedNum": 0
}
Takes 0.002411s.
> db.exec("select * from emp.employees where id=3");
{
"_id": {
"$oid": "5ffee5c77606f131940aa9e3"
},
"birth": "2020-12-13",
"id": 3,
"name": "second"
}
Return 1 row(s).
Takes 0.002100s.
删除
标准的delete语法，再次查询已经没有记录。
> db.execUpdate("delete from emp.employees where id=3");
{
"DeletedNum": 1
}
Takes 0.002337s.
> db.exec("select * from emp.employees where id=3");
Return 0 row(s).
Takes 0.001677s.
总结
通过SQL类型的操作，进行数据的增删改查。其中exec用于查询，execUpdate用于增加，更新和删除。语法与标准SQL一致。