#gojx
gojx is a storage engine use simple kv map as documentation. It provides simple api methods to operate value in storage. It can be used as embedded storage.
gojx saves real data in files. so create a *gojx.Storage in directory.
import "github.com/fuxiaohei/gojx"
s,e := gojx.NewStorage("data",gojx.MAPPER_JSON)
if e != nil{
panic(e) // remember error
}Then register a struct to storage. So far storage can save the struct value.
type User struct {
Id int `jx:"pk"`
UserName string `jx:"index"`
Password string
Email string `jx:"index"`
}
type School struct {
Id int `jx:"pk"`
Address string
Rank int `jx:"index"`
}
s.Register(new(User),1000)
s.Register(new(School),1000)jx:"pk" means primary key for this value, only support int type.
jx:"index" means index for this value, support basic types. If field is index, storage can query data by condition with value in this field.
1000 means how many items saving in a file. If putting 1001st *User, storage writes a new file to saving.
put a new value into storage:
u := new(User)
u.UserName = "abcdef"
u.Password = "12345678"
u.Email = "abcdef@xyz.com"
e := s.Put(u) // u.Id is 1, as first one. remember error.Put only support struct pointer.
The pk field u.Id is assigned as max in storage. Pk is auto increment one by one.
If you set u.Id is over max value in storage, use u.Id as max , then increase pk for next putting.
u := new(User)
u.Id = 999
//.....
e := s.Put(u) // u.Id is 999, the next putting value without pk is 1000.
u2 := new(User)
u.Id = 666
//......
e = s.Put(u) // u.Id is < 999, so use 1000 as u.Id not 666.get value by pk :
u := &User{Id:100}
e := s.Get(u)
if e == gojx.ErrorNoData{
println("get no data")
}else{
println(u.UserName) // if found, field is filled.
}
Get only support struct pointer and by pk field.
If value is not registered, return error.
If value is found, u is filled by value.
update value by pk:
u := new(User)
u.Id = 1
u.UserName = "mnopq"
u.Password = "9876543"
u.Email = "xyz@abc.com"
e := s.Update(u)
if e == gojx.ErrorNoData{
// update not-exist data
}delete value by pk:
u := new(User)
u.Id = 1
e := s.Delete(u)
if e == gojx.ErrorNoData{
// delete not-exist data
}