README
¶
simdb
A simple json db in GO
I sometimes write programs for RaspberryPi using nodejs and use a json file as a data storage. There are so many libraries in nodejs to deal with json file as a data storage. I could'nt find a similar library in GO to use in GO based RPi projects. So decided to write one.
Keep in mind this library can be used in less data intensive applications. I normally use these kind of json data to store execution rules for sensors, etc.
Go Doc https://godoc.org/github.com/sonyarouje/simdb
What it does? This library enables to store, retrieve, update and delete data from the json db.
Usage Let's have a look at, how to store some data and manipulate them using simd.
package main
import db "github.com/sonyarouje/simdb"
type Customer struct {
CustID string `json:"custid"`
Name string `json:"name"`
Address string `json:"address"`
Contact Contact
}
type Contact struct {
Phone string `json:"phone"`
Email string `json:"email"`
}
//ID any struct that needs to persist should implement this function defined
//in Entity interface.
func (c Customer) ID() (jsonField string, value interface{}) {
value=c.CustID
jsonField="custid"
return
}
func main() {
driver, err:=db.New("data")
if err!=nil {
panic(err)
}
customer:=Customer {
CustID:"CUST1",
Name:"sarouje",
Address: "address",
Contact: Contact {
Phone:"45533355",
Email:"someone@gmail.com",
},
}
}
//creates a new Customer file inside the directory passed as the parameter to New()
//if the Customer file already exist then insert operation will add the customer data to the array
err=driver.Insert(customer)
if err!=nil {
panic(err)
}
//GET ALL Customer
//opens the customer json file and filter all the customers with name sarouje.
//AsEntity takes a pointer to Customer array and fills the result to it.
//we can loop through the customers array and retireve the data.
var customers []Customer
err=driver.Open(Customer{}).Where("name","=","sarouje").Get().AsEntity(&customers)
if err!=nil {
panic(err)
}
//GET ONE Customer
//First() will return the first record from the results
//AsEntity takes a pointer to Customer variable (not an array pointer)
var customerFrist Customer
err=driver.Open(Customer{}).Where("custid","=","CUST1").First().AsEntity(&customerFrist)
if err!=nil {
panic(err)
}
//Update function uses the ID() to get the Id field/value to find the record and update the data.
customerFrist.Name="Sony Arouje"
err=driver.Update(customerFrist)
if err!=nil {
panic(err)
}
//Delete
toDel:=Customer{
CustID:"CUST1",
}
err=driver.Delete(toDel)
}
Started as a library to learn GO.
Some of the codes to apply json filtering are borrowed from https://github.com/thedevsaddam/gojsonq
Documentation
¶
Overview ¶
Package db A simple library to persist structs in json file and perform queries and CRUD operations
Index ¶
- Constants
- Variables
- type Driver
- func (d *Driver) AsEntity(output interface{}) (err error)
- func (d *Driver) Delete(entity elemental.Identifiable) (err error)
- func (d *Driver) Errors() []error
- func (d *Driver) First() *Driver
- func (d *Driver) Get() *Driver
- func (d *Driver) Insert(entity elemental.Identifiable) (err error)
- func (d *Driver) Open(entity elemental.Identifiable) *Driver
- func (d *Driver) Raw() interface{}
- func (d *Driver) RawArray() []interface{}
- func (d *Driver) Update(entity elemental.Identifiable) (err error)
- func (d *Driver) Upsert(entity elemental.Identifiable) (err error)
- func (d *Driver) Where(key, cond string, val interface{}) *Driver
- type QueryFunc
Constants ¶
const (
IdentifierKey = "ID"
)
Variables ¶
var ErrRecordNotFound = errors.New("record not found")
var ErrUpdateFailed = errors.New("update failed, no record(s) to update")
Functions ¶
This section is empty.
Types ¶
type Driver ¶
type Driver struct {
// contains filtered or unexported fields
}
Driver contains all the state of the db.
func New ¶
New creates a new database driver. Accepts the directory name to store the db files. If the passed directory not exist then will create one.
driver, err:=db.New("customer")
func (*Driver) AsEntity ¶
AsEntity will converts the map to the passed structure pointer. should call this function after calling Get() or First(). This function will convert the result of Get or First operation to the passed structure type 'output' variable should be a pointer to a structure or stucture array. Function returns error in case of any errors in conversion.
First()
var custOut Customer
err:=driver.Open(Customer{}).First().AsEntity(&custOut)
fmt.Printf("%#v", custOut)
this function will fill the custOut with the values from the map
Get()
var customers []Customer
err:=driver.Open(Customer{}).Get().AsEntity(&customers)
func (*Driver) Delete ¶
func (d *Driver) Delete(entity elemental.Identifiable) (err error)
Delete the record from the json db based on the id field/value pair
custToDelete:=Customer {
CustID:"CUST1",
}
err:=driver.Delete(custToDelete)
func (*Driver) First ¶
First return the first record matching the condtion.
driver.Open(Customer{}).Where("custid","=","CUST1").First()
func (*Driver) Get ¶
Get the result from the json db as an array. If no where condition then return all the data from json db
Get based on a where condition
driver.Open(Customer{}).Where("name","=","sarouje").Get()
Get all records
driver.Open(Customer{}).Get()
func (*Driver) Insert ¶
func (d *Driver) Insert(entity elemental.Identifiable) (err error)
Insert the entity to the json db. Insert will identify the type of the entity and insert the entity to the specific json file based on the type of the entity. If the db file not exist then will create a new db file
customer:=Customer {
CustID:"CUST1",
Name:"sarouje",
Address: "address",
Contact: Contact {
Phone:"45533355",
Email:"someone@gmail.com",
},
}
err:=driver.Insert(customer)
func (*Driver) Open ¶
func (d *Driver) Open(entity elemental.Identifiable) *Driver
Open will open the json db based on the entity passed. Once the file is open you can apply where conditions or get operation.
driver.Open(Customer{})
Open returns a pointer to Driver, so you can chain methods like Where(), Get(), etc
func (*Driver) RawArray ¶
func (d *Driver) RawArray() []interface{}
RawArray will return the data in map array type
func (*Driver) Update ¶
func (d *Driver) Update(entity elemental.Identifiable) (err error)
Update the json data based on the id field/value pair
customerToUpdate:=driver.Open(Customer{}).Where("custid","=","CUST1").First()
customerToUpdate.Name="Sony Arouje"
err:=driver.Update(customerToUpdate)
Should not change the ID field when updating the record.
func (*Driver) Upsert ¶
func (d *Driver) Upsert(entity elemental.Identifiable) (err error)
Upsert function will try updating the passed entity. If no records to update then do the Insert operation.
customer := Customer{
CustID: "CU4",
Name: "Sony Arouje",
Address: "address",
Contact: Contact{
Phone: "45533355",
Email: "someone@gmail.com",
},
}
driver.Upsert(customer)
Source Files