Deta Base SDK

The Deta library is the easiest way to store and retrieve data from your Deta Base. Currently we support JavaScript (Node + Browser), Python 3 and Go. Drop us a line if you want us to support your favorite language.

note

A "Deta Base" instance is a collection of data not unlike a Key-Value store, a MongoDB collection or a PostgreSQL/MySQL table. It will grow with your app's needs.

note

If your database keys have special characters (like &,/, @ etc) that are url-reserved or url-unsafe, please use the latest sdk versions to prevent unexpected behavior.

Installing the Deta Library#

First, install the Deta library in your project's directory.

JavaScript
Python
Go

Using NPM:

npm install deta

Using Yarn:

yarn add deta

Instantiating#

To start working with your Base, you need to import the Deta class and initialize it with a Project Key. Then instantiate a subclass called Base with a database name of your choosing.

Deta Bases are created for you automatically when you start using them.

JavaScript
Python
Go

const { Deta } = require('deta'); // import Deta

// Initialize with a Project Key
const deta = Deta('project key'); 

// This how to connect to or create a database.
const db = deta.Base('simple_db'); 

// You can create as many as you want without additional charges.
const books = deta.Base('books'); 

note

If you are using Deta Base within a Deta Micro, the Deta SDK comes pre-installed and a valid project key is pre-set in the Micro's environment. There is no need to install the SDK or pass a key in the initialization step.

const { Deta } = require('deta');

const deta = Deta(); 

note

If you are using the deta npm package of 0.0.6 or below, Deta is the sinlge default export and should be imported as such.

const Deta = require('deta');

warning

Your project key is confidential and meant to be used by you. Anyone who has your project key can access your database. Please, do not share it or commit it in your code.

Using#

Deta's Base class offers the following methods to interact with your Deta Base:

put – Stores an item in the database. It will update an item if the key already exists.

insert – Stores an item in the database but raises an error if the key already exists. (2x slower than put).

get – Retrieves an item from the database by its key.

fetch – Retrieves multiple items from the database based on the provided (optional) filters.

delete – Deletes an item from the database.

update – Updates an item in the database.

Put#

put is the fastest way to store an item in the database.

In the case you do not provide us with a key, we will auto generate a 12 char long string as a key.

You can also use put when you want to update an item in the database.

JavaScript
Python
Go

async put(data, key=null)

Parameters#

data (required) – Accepts: object (serializable), string, number, boolean and array.
- Description: The data to be stored.
key (optional) – Accepts: string and null
- Description: the key (aka ID) to store the data under. Will be auto generated if not provided.

Code Example#

const Deta = require('deta');

const deta = Deta("project key");
const db = deta.Base("simple_db");

// you can store objects
db.put({name: "alex", age: 77})  // A key will be automatically generated
db.put({name: "alex", age: 77}, "one")  // We will use "one" as a key
db.put({name: "alex", age: 77, key:"one"})  // The key could also be included in the object itself

// or store simple types:
db.put("hello, worlds")
db.put(7)
db.put("success", "smart_work") // "success" is the value and "smart_work" is the key.
db.put(["a", "b", "c"], "my_abc")

Returns#

put returns a promise which resolves to the item on a successful put, otherwise it throws an Error.

put(data: typing.Union[dict, list, str, int, float, bool], key:str = None):

Parameters#

data (required) – Accepts: dict, str, int, float, bool and list.
- Description: The data to be stored.
key (optional) – Accepts: str and None
- Description: the key (aka ID) to store the data under. Will be auto generated if not provided.

Code Example#

from deta import Deta
deta = Deta("project key")  
db = deta.Base("simple_db")

# you can store objects
db.put({"name": "alex", "age": 77})  # A key will be automatically generated
db.put({"name": "alex", "age": 77}, "one")  # We will use "one" as a key
db.put({"name": "alex", "age": 77, "key": "one"})  # The key could also be included in the object itself

# or store simple types:
db.put("hello, worlds")
db.put(7)
db.put("success", "smart_work")  # "success" is the value and "smart_work" is the key.
db.put(["a", "b", "c"], "my_abc")

Returns#

put returns the item on a successful put, otherwise it raises an Error.

Put(item interface{}) (string, error)

Parameters#

item : The item to be stored, should be a struct or a map. If the item is a struct provide the field keys for the data with json struct tags. The key of the item must have a json struct tag of key.

Code Example#

import (
    "fmt"
    "github.com/deta/deta-go"
)

type User struct{
    Key string `json:"key"` // json struct tag 'key' used to denote the key
    Username string `json:"username"`
    Active bool `json:"active"`
    Age int `json:"age"`
    Likes []string `json:"likes"`
}

func main(){
    // error ignored for brevity
    d, _ := deta.New("project key")
    db, _ := d.NewBase("users")

    // a user
    u := &User{
        Key: "kasdlj1",
        Username: "jimmy",
        Active: true,
        Age: 20,
        Likes: []string{"ramen"},
    }

    // put item in the database
    key, err := db.Put(u)
    if err != nil {
        fmt.Println("Failed to put item:", err)
        return
    }
    fmt.Println("Successfully put item with key:", key)

    // can also use a map
    um := map[string]interface{}{
      "key": "kasdlj1",
      "username": "jimmy",
      "active": true,
      "age": 20,
      "likes": []string{"ramen"},
    }

    key, err = db.Put(um)
    if err != nil {
        fmt.Println("Failed to put item:", err)
        return
    }
    fmt.Println("Successfully put item with key:", key)
}

Returns#

Returns the key of the item stored and an error. Possible error values:

ErrBadItem : bad item, item is of unexpected type
ErrBadRequest: item caused a bad request response from the server
ErrUnauthorized: unuathorized
ErrInternalServerError: internal server error

Get#

get retrieves an item from the database by it's key.

JavaScript
Python
Go

async get(key)

Parameters#

key (required) – Accepts: string
- Description: the key of which item is to be retrieved.

Code Example#

const item = await db.get('one'); // retrieving item with key "one"

Returns#

If the record is found, the promise resolves to:

{
  name: 'alex', age: 77, key: 'one'
}

If not found, the promise will resolve to null.

get(key: str)

Parameter Types#

key (required) – Accepts: str
- Description: the key of which item is to be retrieved.

Code Example#

item = db.get("one") # retrieving item with key "one"

Returns#

If the record is found:

{
  "name": "alex", "age": 77, "key": "one"
} 

If not found, the function will return None.

Get(key string, dest interface{}) error

Parameters#

key: the key of the item to be retrieved
dest: the result will be stored into the value pointed by dest

Code Example#

import (
    "fmt"
    "github.com/deta/deta-go"
)

type User struct{
    Key string `json:"key"` // json struct tag 'key' used to denote the key
    Username string `json:"username"`
    Active bool `json:"active"`
    Age int `json:"age"`
    Likes []string `json:"likes"`
}

func main(){
    // error ignored for brevity
    d, _ := deta.New("project key")
    db, _ := d.NewBase("users")

    // a variable to store the result 
    var u User 
    
    // get item
    // returns ErrNotFound if no item was found
    err := db.Get("kasdlj1", &u)
    if err != nil{
        fmt.Println("Failed to get item:", err)
    }
}

Returns#

Returns an error. Possible error values:

ErrNotFound: no item with such key was found
ErrBadDestination: bad destination, result could not be stored onto dest
ErrUnauthorized: unauthorized
ErrInternalServerError: internal server error

Delete#

delete deletes an item form the database provided a key.

JavaScript
Python
Go

async delete(key)

Parameters#

key (required) – Accepts: string
- Description: the key of which item is to be deleted.

Code Example#

const res = await db.delete("one")

Returns#

Always returns a promise which resolves to null, even if the key does not exist.

delete(key: str)

Parameters#

key (required) – Accepts: str
- Description: the key of which item is to be deleted.

Code Example#

res = db.delete("one")

Returns#

Always returns None, even if the key does not exist.

Delete(key string) error

Parameters#

key: the key of the item to be deleted

Code Example#

// delete item
// returns a nil error if item was not found
err := db.Delete("dakjkfa")
if err != nil {
  fmt.Println("Failed to delete item:", err)
}

Returns#

Returns an error. A nil error is returned if no item was found with provided key. Possible error values:

ErrUnauthorized: unauthorized
ErrInternalServerError: internal server error

Insert#

The insert method inserts a single item into a Base, but is unique from put in that it will raise an error of the key already exists in the database.

insert is roughly 2x slower than put.

JavaScript
Python
Go

async insert(data, key=null)

Parameters#

data (required) – Accepts: object (serializable), string, number, boolean and array.
- Description: The data to be stored.
key (optional) – Accepts: string and null
- Description: the key (aka ID) to store the data under. Will be auto generated if not provided.

Code Example#

// will succeed, a key will be auto-generated
const res1 = await db.insert('hello, world');

// will succeed.
const res2 = await db.insert({message: 'hello, world'}, 'greeting1');

// will raise an error as key "greeting1" already existed.
const res3 = await db.insert({message: 'hello, there'}, 'greeting1');

Returns#

Returns a promise which resolves to the item on a successful insert, and throws an error if the key already exists.

insert(data: typing.Union[dict, list, str, int, float, bool], key:str = None):

Parameters#

data (required) – Accepts: dict, str, int, float, bool and list.
- Description: The data to be stored.
key (optional) – Accepts: str and None
- Description: the key (aka ID) to store the data under. Will be auto generated if not provided.

Code Example#

# will succeed, a key will be auto-generated
res1 = db.insert("hello, world")

# will succeed.
res2 = db.insert({"message": "hello, world"}, "greeting1")

# will raise an error as key "greeting1" already existed.
res3 = db.insert({"message": "hello, there"}, "greeting1")

Returns#

Returns the item on a successful insert, and throws an error if the key already exists.

Insert(item interface{}) (string, error)

Parameters#

item : similar to item parameter to Put

Code Example#

import (
    "fmt"
    "github.com/deta/deta-go"
)

type User struct{
    Key string `json:"key"` // json struct tag 'key' used to denote the key
    Username string `json:"username"`
    Active bool `json:"active"`
    Age int `json:"age"`
    Likes []string `json:"likes"`
}

func main(){
    // error ignored for brevity
    d, _ := deta.New("project key")
    db, _ := d.NewBase("users")

    // a user
    u := &User{
        Key: "kasdlj1",
        Username: "jimmy",
        Active: true,
        Age: 20,
        Likes: []string{"ramen"},
    }

    // insert item in the database
    key, err := db.Insert(u)
    if err != nil {
        fmt.Println("Failed to insert item:", err)
        return
    }
    fmt.Println("Successfully inserted item with key:", key)
}

Returns#

Returns the key of the item inserted and an error. Possible error values:

ErrConflict : if item with provided key already exists
ErrBadItem: bad item, if item is of unexpected type
ErrBadRequest: item caused a bad request response from the server
ErrUnauthorized: unauthorized
ErrInternalServerError: internal server error

Put Many#

The Put Many method puts up to 25 items into a Base at once on a single call.

JavaScript
Python
Go

async putMany(items)

Parameters#

items (required) – Accepts: Array of items, where each "item" can be an object (serializable), string, number, boolean or array.
- Description: The list of items to be stored.

Code Example#

const res1 = await db.putMany([
  {"name": "Beverly", "hometown": "Copernicus City", "key": "one"}, // key provided
  "dude", // key auto-generated 
  ["Namaskāra", "marhabaan", "hello", "yeoboseyo"] // key auto-generated 
]);

Returns#

Returns a promise which resolves to the put items on a successful insert, and throws an error if you attempt to put more than 25 items.

{
    "processed": {
        "items": [
            {
                "hometown": "Copernicus City",
                "key": "one",
                "name": "Beverly"
            },
            {
                "key": "jyesxxlrezo0",
                "value": "dude"
            },
            {
                "key": "5feqybn7lb05",
                "value": [
                    "Namaskāra",
                    "hello",
                    "marhabaan",
                    "yeoboseyo"
                ]
            }
        ]
    }
}

put_many(items):

Parameters#

items (required) – Accepts: list of items, where each "item" can be an dict (JSON serializable), str, int, bool, float or list.
- Description: The list of items to be stored.

Code Example#

res_one = db.put_many([
  {"name": "Beverly", "hometown": "Copernicus City", "key": "one"}, // key provided
  "dude", // key auto-generated 
  ["Namaskāra", "marhabaan", "hello", "yeoboseyo"] // key auto-generated 
])

Returns#

Returns a promise which resolves to the put items on a successful insert, and raises an error if you attempt to put more than 25 items.

{
    "processed": {
        "items": [
            {
                "hometown": "Copernicus City",
                "key": "one",
                "name": "Beverly"
            },
            {
                "key": "jyesxxlrezo0",
                "value": "dude"
            },
            {
                "key": "5feqybn7lb05",
                "value": [
                    "Namaskāra",
                    "hello",
                    "marhabaan",
                    "yeoboseyo"
                ]
            }
        ]
    }
}

PutMany(items interface{}) ([]string, error)

Parameters:#

items: a slice of items, each item in the slice similar to the item parameter in Put

Code Example:#

import (
    "fmt"
    "github.com/deta/deta-go"
)

type User struct{
    Key string `json:"key"` // json struct tag 'key' used to denote the key
    Username string `json:"username"`
    Active bool `json:"active"`
    Age int `json:"age"`
    Likes []string `json:"likes"`
}

func main(){
    // error ignored for brevity
    d, _ := deta.New("project key")
    db, _ := d.NewBase("users")

    // users
    u1 := &User{
        Key: "kasdlj1",
        Username: "jimmy",
        Active: true,
        Age: 20,
        Likes: []string{"ramen"},
    }
    u2 := &User{
      Key: "askdjf",
      Username: "joel",
      Active: true,
      Age: 23,
      Likes: []string{"coffee"},
    }
    users := []*User{u1, u2}

    // put items in the database
    keys, err := db.PutMany(users)
    if err != nil {
        fmt.Println("Failed to put items:", err)
        return
    }
    fmt.Println("Successfully put item with keys:", keys)
}

Returns#

Returns the list of keys of the items stored and an error. In case of an error, none of the items are stored. Possible error values:

ErrTooManyItems: if there are more than 25 items
ErrBadItem: bad item/items, one or more item of unexpected type
ErrBadRequest: one or more item caused a bad request response from the server
ErrUnauthorized: unauthorized
ErrInternalServerError: internal server error

Update#

update updates an existing item from the database.

JavaScript
Python
Go

async update(updates, key)

Parameters#

updates (required) - Accepts: object (JSON serializable)
- Description: a json object describing the updates on the item
key (required) – Accepts: string
- Description: the key of the item to be updated.

Update operations#

Set : Set is practiced through normal key-value pairs. The operation changes the values of the attributes provided in the set object if the attribute already exists. If not, it adds the attribute to the item with the corresponding value.
Increment: Increment incrementes the value of an attribute. The attribute's value must be a number. The util base.util.increment(value) should be used to increment the value. The default value is 1 if not provided and it can also be negative.
Append: Append appends to a list. The util base.util.append(value) should be used to append the value. The value can be a primitive type or an array.
Prepend: Prepend prepends to a list. The util base.util.prepend(value) should be used to prepend the value. The value can be a primitive type or an array.
Trim: Trim removes an attribute from the item, the util base.util.trim() should be used as the value of an attribute.

Code Example#

Consider we have the following item in a base const users = deta.Base('users'):

{
  "key": "user-a",
  "username": "jimmy",
  "profile": {
    "age": 32,
    "active": false,
    "hometown": "pittsburgh" 
  },
  "on_mobile": true,
  "likes": ["anime"],
  "purchases": 1
}

Then the following update operation :

const updates = {
  "profile.age": 33, // set profile.age to 33
  "profile.active": true, // set profile.active to true
  "profile.email": "jimmy@deta.sh", // create a new attribute 'profile.email'
  "profile.hometown": users.util.trim(), // remove 'profile.hometown'
  "on_mobile": users.util.trim(), // remove 'on_mobile'
  "purchases": users.util.increment(2), // increment 'purchases' by 2, default value is 1
  "likes": users.util.append("ramen") // append 'ramen' to 'likes', also accepts an array 
}

const res = await db.update(updates, "user-a");

Results in the following item in the base:

{
  "key": "user-a",
  "username": "jimmy",
  "profile": {
    "age": 33,
    "active": true,
    "email": "jimmy@deta.sh"
  },
  "likes": ["anime", "ramen"],
  "purchases": 3
}

Returns#

If the item is updated, the promise resolves to null. Otherwise, an error is raised.

update(updates:dict, key:str)

Parameters#

updates (required) - Accepts: dict (JSON serializable)
- Description: a dict describing the updates on the item
key (required) – Accepts: string
- Description: the key of the item to be updated.

Update operations#

Set : Set is practiced through normal key-value pairs. The operation changes the values of the attributes provided in the set dict if the attribute already exists. If not, it adds the attribute to the item with the corresponding value.
Increment: Increment incrementes the value of an attribute. The attribute's value must be a number. The util base.util.increment(value) should be used to increment the value. The default value is 1 if not provided and it can also be negative.
Append: Append appends to a list. The util base.util.append(value) should be used to append the value. The value can be a primitive type or a list.
Prepend: Prepend prepends to a list. The util base.util.prepend(value) should be used to prepend the value. The value can be a primitive type or a list.
Trim: Trim removes an attribute from the item, the util base.util.trim() should be used as the value of an attribute.

Code Example#

Consider we have the following item in a base users = deta.Base('users'):

{
  "key": "user-a",
  "username": "jimmy",
  "profile": {
    "age": 32,
    "active": false,
    "hometown": "pittsburgh" 
  },
  "on_mobile": true,
  "likes": ["anime"],
  "purchases": 1 
}

Then the following update operation:

updates = {
  "profile.age": 33,  # set profile.age to 33
  "profile.active": True, # set profile.active to true
  "profile.email": "jimmy@deta.sh", # create a new attribute 'profile.email'
  "profile.hometown": users.util.trim(), # remove 'profile.hometown'
  "on_mobile": users.util.trim(), # remove 'on_mobile'
  "purchases": users.util.increment(2), # increment by 2, default value is 1
  "likes": users.util.append("ramen") # append 'ramen' to 'likes', also accepts a list 
}

db.update(updates, "user-a")

Results in the following item in the base:

{
  "key": "user-a",
  "username": "jimmy",
  "profile": {
    "age": 33,
    "active": true,
    "email": "jimmy@deta.sh"
  },
  "likes":["anime", "ramen"],
  "purchases": 3
}

Returns#

If the item is updated, returns None. Otherwise, an exception is raised.

Update(key stirng, updates Updates) error

Parameters#

key: the key of the item to update
updates : updates applied to the item, is of type deta.Updates which is a map[string]interface{}

Update operations#

Set : Set is practiced through normal key-value pairs. The operation changes the values of the attributes provided if the attribute already exists. If not, it adds the attribute to the item with the corresponding value.
Increment: Increment incrementes the value of an attribute. The attribute's value must be a number. The util Base.Util.Increment(value interface{}) should be used to increment the value. The value can also be negative.
Append: Append appends to a list. The util Base.Util.Append(value interface{}) should be used to append the value. The value can be a slice.
Prepend: Prepend prepends to a list. The util Base.Util.Prepend(value interface{}) should be used to prepend the value. The value can be a slice.
Trim: Trim removes an attribute from the item, the util Base.Util.Trim() should be used as the value of an attribute.

Code Example#

Consider we have the following item in a base users:

{
  "key": "user-a",
  "username": "jimmy",
  "profile": {
    "age": 32,
    "active": false,
    "hometown": "pittsburgh" 
  },
  "on_mobile": true,
  "likes": ["anime"],
  "purchases": 1
}

Then the following update operation :

// define the updates
updates := deta.Updates{
  "profile.age": 33, // set profile.age to 33
  "profile.active": true, // set profile.active to true
  "profile.email": "jimmy@deta.sh", // create a new attribute 'profile.email'
  "profile.hometown": users.Util.Trim(), // remove 'profile.hometown'
  "on_mobile": users.Util.Trim(), // remove 'on_mobile'
  "purchases": users.Util.Increment(2), // increment 'purchases' by 2 
  "likes": users.Util.Append("ramen") // append 'ramen' to 'likes', also accepts a slice 
}

// update
err := users.Util.Update("user-a", updates);

Results in the following item in the base:

{
  "key": "user-a",
  "username": "jimmy",
  "profile": {
    "age": 33,
    "active": true,
    "email": "jimmy@deta.sh"
  },
  "likes": ["anime", "ramen"],
  "purchases": 3
}

Returns#

Returns an error. Possible error values:

ErrBadRequest: the update operation caused a bad request response from the server
ErrUnauthorized: unauthorized
ErrInternalServerError: internal server error

Fetch#

Fetch retrieves a list of items matching a query. It will retrieve everything if no query is provided.

A query is composed of a single query object or a list of queries.

In the case of a list, the indvidual queries are OR'ed.

JavaScript
Python
Go

async fetch(query, pages=10, buffer=null)

Parameters#

query: is a single query object or list of queries. If omitted, you will get all the items in the database (up to 1mb).
pages how many pages of items should be returned.
buffer: the number of items which will be returned for each iteration (aka "page") on the return iterable. This is useful when your query is returning more than 1mb of data, so you could buffer the results in smaller chunks.

Code Example#

For the examples, let's assume we have a Base with the following data:

[
  {
    "key": "key-1",
    "name": "Wesley",
    "age": 27,
    "hometown": "San Francisco",
  },
  {
    "key": "key-2",
    "name": "Beverly",
    "age": 51,
    "hometown": "Copernicus City",
  },
  {
    "key": "key-3",
    "name": "Kevin Garnett",
    "age": 43,
    "hometown": "Greenville",
  }
]

const {value: myFirstSet} = await db.fetch({"age?lt": 30}).next();
const {value: mySecondSet} = await db.fetch([
  { "age?gt": 50 },
  { "hometown": "Greenville" }
]).next();

... will come back with following data:

`myFirstSet`:#

[
  {
    "key": "key-1",
    "name": "Wesley",
    "age": 27,
    "hometown": "San Francisco",
  }
]

`mySecondSet`:#

[
  {
    "key": "key-2",
    "name": "Beverly",
    "age": 51,
    "hometown": "Copernicus City",
  },
  {
    "key": "key-3",
    "name": "Kevin Garnett",
    "age": 43,
    "hometown": "Greenville",
  },
]

Returns#

A promise which resolves to a generator of objects that meet the query criteria.

The total number of items will not exceed the defined using buffer and `pages. Max. number of items

Iterating through the generator yields arrays containing objects, each array of max length buffer.

Example using buffer, pages#

const foo = async (myQuery, bar) => {

  items = db.fetch(myQuery, 10, 20) // items is up to the limit length (10*20)

  for await (const subArray of items) // each subArray is up to the buffer length, 20
    bar(subArray)
}

fetch(query=None, buffer=None, pages=10):

Parameters#

query: is a single query object (dict) or list of queries. If omitted, you will get all the items in the database (up to 1mb).
pages how many pages of items should be returned.
buffer: the number of items which will be returned for each iteration (aka "page") on the return iterable. This is useful when your query is returning more 1mb of data, so you could buffer the results in smaller chunks.

Code Example#

For the examples, let's assume we have a Base with the following data:

[
  {
    "key": "key-1",
    "name": "Wesley",
    "age": 27,
    "hometown": "San Francisco",
  },
  {
    "key": "key-2",
    "name": "Beverly",
    "age": 51,
    "hometown": "Copernicus City",
  },
  {
    "key": "key-3",
    "name": "Kevin Garnett",
    "age": 43,
    "hometown": "Greenville",
  }
]

my_first_set = next(db.fetch({"age?lt": 30}))
my_second_set = next(db.fetch([{"age?gt": 50}, {"hometown": "Greenville"}]))

... will come back with following data:

`my_first_set`:#

[
  {
    "key": "key-1",
    "name": "Wesley",
    "age": 27,
    "hometown": "San Francisco",
  }
]

`my_second_set`:#

[
  {
    "key": "key-2",
    "name": "Beverly",
    "age": 51,
    "hometown": "Copernicus City",
  },
  {
    "key": "key-3",
    "name": "Kevin Garnett",
    "age": 43,
    "hometown": "Greenville",
  },
]

Returns#

A generator of objects that meet the query criteria.

The total number of items will not exceed the defined using buffer and `pages. Max. number of items

Iterating through the generator yields lists containing objects, each list of max length buffer.

Example using buffer, pages#

def foo(my_query, bar):
  items = db.fetch(my_query, pages=10, buffer=20) # items is up to the limit length (10*20)

  for sub_list in items: # each sub_list is up to the buffer length, 10
    bar(sub_list)

Fetch(i *FetchInput) error

Parameters#

i: is a pointer to a FetchInput
// FetchInput input to Fetch operation
type FetchInput struct {
// filters to apply to items
// A nil value applies no queries and fetches all items
Q Query
// the destination to store the results
Dest interface{}
// the maximum number of items to fetch
// value of 0 or less applies no limit
Limit int
// the last key evaluated in a paginated response
// leave empty if not a subsequent fetch request
LastKey string
}
- Q: fetch query, is of type deta.Query which is a []map[string]interface{}
- Dest: the results will be stored into the value pointed by Dest
- Limit: the maximum number of items to fetch, value of 0 or less applies no limit
- LastKey: the last key evaluated in a paginated response, leave empty if not a subsequent fetch request

Code Example#

import (
    "github.com/deta/deta-go"
)

type User struct {
    Key string `json:"key"`
    Name string `json:"name"`
    Age int `json:"age"`
    Hometown string `json:"hometown"`
}

func main(){
    // errors ignored for brevity
    d, _ := deta.New("project key")
    db, _ := deta.NewBase("users")

    // query to get users with age less than 30
    query := deta.Query{
      {"age?lt": 50},
    }
    
    // variabe to store the results
    var results []*User

    // fetch items
    _, err := db.Fetch(&deta.FetchInput{
      Q: query,
      Dest: &results,
    })
    if err != nil {
        fmt.Println("failed to fetch items:", err) 
    }
}

... results will have the following data:

[
  {
    "key": "key-1",
    "name": "Wesley",
    "age": 27,
    "hometown": "San Francisco",
  },
  {
    "key": "key-3",
    "name": "Kevin Garnett",
    "age": 43,
    "hometown": "Greenville",
  },
]

Paginated example#

import (
    "github.com/deta/deta-go"
)

type User struct {
    Key string `json:"key"`
    Name string `json:"name"`
    Age int `json:"age"`
    Hometown string `json:"hometown"`
}

func main(){
    // errors ignored for brevity
    d, _ := deta.New("project key")
    db, _ := deta.NewBase("users")

    // query to get users with age less than 30
    query := deta.Query{
      {"age?lt": 50},
    }
    
    // variabe to store the results
    var results []*User

    // variable to store the page
    var page []*User

    // fetch input 
    i := &deta.FetchInput{
      Q: query,      
      Dest: &page,
      Limit: 1, // limit provided so each page will only have one item
    } 
    
    // fetch items
    lastKey, err := db.Fetch(i)
    if err != nil {
        fmt.Println("failed to fetch items:", err) 
        return
    }

    // append page items to results
    results = append(allResults, page...)

    // get all pages
    for lastKey != ""{
      // provide the last key in the fetch input
      i.LastKey = lastKey

      // fetch
      lastKey, err := db.Fetch(i)
      if err != nil {
          fmt.Println("failed to fetch items:", err)
          return
      }

      // append page items to all results
      results = append(allResults, page...)
    }
}

Returns#

Returns an error. Possible error values:

ErrBadDestination: bad destination, results could not be stored onto dest
ErrBadRequest: the fetch request caused a bad request response from the server
ErrUnauthorized: unauthorized
ErrInternalServerError: internal server error

Queries#

Queries are regular objects/dicts/maps with conventions for different operations.

Equal#

{"age": 22, "name": "Beverly"}

// hierarchical
{"user.profile.age": 22, "user.profile.name": "Beverly"}

{"fav_numbers": [2, 4, 8]}

{"time": {"day": "Tuesday", "hour": "08:00"}}

Not Equal#

{"user.profile.age?ne": 22}

Less Than#

{"user.profile.age?lt": 22}

Greater Than#

{"user.profile.age?gt": 22}

Less Than or Equal#

{"user.profile.age?lte": 22}

Greater Than or Equal#

{"user.profile.age?gte": 22}

Prefix#

{"user.id?pfx": "afdk"}

Range#

{"user.age?r": [22, 30]}

Contains#

{
  // if user email contains the substring @deta.sh
  "user.email?contains": "@deta.sh" 
}

{
  // if berlin is in a list of places lived 
  "user.places_lived_list?contains": "berlin"
}

Not Contains#

{
  // if user email does not contain @deta.sh
  "user.email?not_contains": "@deta.sh" // 'user.email?!contains' also valid
}

{
  // if berlin is not in a list of places lived
  "user.places_lived_list?not_contains": "berlin" // 'user.places_lived_list?!contains' also valid
}

note

?contains and ?not_contains only works for a list of strings if checking for membership in a list; it does not apply to list of other data types. You can store your lists always as a list of strings if you want to check for membership.

Contact#

hello@deta.sh

note

note

Installing the Deta Library#

Instantiating#

note

note

note

warning

Using#

Put#

Parameters#

Code Example#

Returns#

Parameters#

Code Example#

Returns#

Parameters#

Code Example#

Returns#

Get#

Parameters#

Code Example#

Returns#

Parameter Types#

Code Example#

Returns#

Parameters#

Code Example#

Returns#

Delete#

Parameters#

Code Example#

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Parameters#

Code Example#

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Parameters#

Code Example#

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Insert#

Parameters#

Code Example#

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Parameters#

Code Example#

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Parameters#

Code Example#

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Put Many#

Parameters#

Code Example#

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Parameters:#

Code Example:#

Returns#

Update#

Parameters#

Update operations#

Code Example#

Returns#

Parameters#

Update operations#

Code Example#

Returns#

Parameters#

Update operations#

Code Example#

Returns#

Fetch#

Parameters#

Code Example#

myFirstSet:#

mySecondSet:#

Returns#

Example using buffer, pages#

Parameters#

`myFirstSet`:#

`mySecondSet`:#

`my_first_set`:#

`my_second_set`:#