15.3 Using Databases from JS Code
From JavaScript node code, you can work with databases, collections, and objects.
Below are code examples with the main concepts.
Working with Collections
All methods can be called using ORM: to create a database js-object, use db.database('database_id') and specify the specific ID of your database (you can find it on the "Database" page in the left menu).
export default async function run({execution_id, input, data, store, db}) {
const database_id = '4da687c4-2ba1-476f-9ff2-c5942aab2fbd'
const database = db.database(database_id)
}
To access collection and object management methods, you need to create a collection js-object:
export default async function run({execution_id, input, data, store, db}) {
const database_id = '4da687c4-2ba1-476f-9ff2-c5942aab2fbd'
const database = db.database(database_id)
const collection = database.collection('collection_name')
}
The collection() method does not create a new collection. If you need to create a new collection, you can call the method await database.createCollection('collection_name'). If such a collection already exists, an error is not returned.
Working with Objects
To create an object in a collection, use the method await collection.createObject(). As a parameter, you can pass a string, number, boolean value, array, or js-object of any nesting. The method returns a string with the object ID:
export default async function run({execution_id, input, data, store, db}) {
const database_id = '4da687c4-2ba1-476f-9ff2-c5942aab2fbd'
const database = db.database(database_id)
const collection = database.collection('collection_name')
const object_id = await collection.createObject({
testField: {
field: "test"
}
})
return {
object_id
}
}
To output a list of objects, use the method await collection.findObjects(limit, offset, filter). The limit parameter sets the number of rows to read in one request, offset - the start of reading shift (standard parameters as for pagination). The filter parameter is optional and can be set as a string (YAML and JSON) or as a js-object:
export default async function run({execution_id, input, data, store, db}) {
const database_id = '4da687c4-2ba1-476f-9ff2-c5942aab2fbd'
const database = db.database(database_id)
const collection = database.collection('collection_name')
const objects1 = await collection.findObjects(50, 0)
const filterStr = \`
conditions:
- operation: "equal"
query:
path: "example"
expected:
value: "example_js"
\`
const objects2 = await collection.findObjects(50, 0, filterStr)
const filterObj = {
conditions: [
{
operation: "equal",
query: {
path: "example"
},
expected: {
value: "example_js"
}
}
]
}
const objects3 = await collection.findObjects(50, 0, filterObj)
return {
objects1,
objects2,
objects3
}
}
To update objects, use the method await collection.updateObjects(filter, updater). The updater parameter, similar to the filter, can be either a string (YAML and JSON) or a js-object. The method returns a number - the count of updated objects:
export default async function run({execution_id, input, data, store, db}) {
const database_id = '4da687c4-2ba1-476f-9ff2-c5942aab2fbd'
const database = db.database(database_id)
const collection = database.collection('collection_name')
const filterStr = \`
conditions:
- operation: "equal"
query:
path: "example"
expected:
value: "example_js"
\`
const updaterStr = \`
items:
- path: "example"
set:
value: "example_js_2"\`
\`
const count1 = await collection.updateObjects(filterStr, updaterStr)
const filterObj = {
conditions: [
{
operation: "equal",
query: {
path: "example"
},
expected: {
value: "example_js_2"
}
}
]
}
const updaterObj = {
items: [
{
path: "example",
set: {
value: "example_js_3"
}
}
]
}
const count2 = await collection.updateObjects(filterObj, updaterObj)
return {
count1,
count2
}
}
Table of All Methods Description
Database JS-object
- Method name: collection(collection_name)
Parameters: collection_name - string
Description: Used to get a collection js-object, which is used for further work with objects.
Return value: Collection js-object
---
- Method name: createCollection(collection_name)
Parameters: collection_name - string
Description: Creates a new collection with the given name. If the collection already exists, no error is returned.
Return value: Collection js-object
---
- Method name: listCollections()
Parameters:
Description: Get a list of collections for the specified database.
Return value: Array of objects:
[
{
"storage_id": "id",
"collection_name": "name"
}
]
Collection JS-object
- Method name: get()
Parameters:
Description: Requests the collection from the database.
Return value: Example of collection:
{
"storage_id": "id",
"collection_name": "name"
}
---
- Method name: updateCollectionName(new_collection_name)
Parameters: new_collection_name - string
Description: Updates the collection name.
Return value:
---
- Method name: truncate()
Parameters:
Description: Deletes all objects in the collection.
Return value:
---
- Method name: delete()
Parameters:
Description: Deletes the collection.
Return value:
---
- Method name: findObjects(limit, offset, filter = '')
Parameters: limit - int
offset - int
filter - string/object (optional parameter)
Description: Searches for objects with or without a filter.
Return value: Array of objects
---
- Method name: getObjectByID(object_id)
Parameters: object_id - string
Description: Gets an object by its ID.
Return value: Object
---
- Method name: createObject(object)
Parameters: object - any JS data type
Description: Creates an object.
Return value: ID of the created object
---
- Method name: updateObjects(filter, updater)
Parameters: filter - string/object
updater - string/object
Description: Updates objects by filter.
Return value: Number of updated objects
---
- Method name: deleteObject(object_id)
Parameters: object_id - string
Description: Deletes an object by its ID.
Return value: If the object existed and was deleted - 1
If the object was not found or already deleted - 0
---
- Method name: deleteObjectsByFilter(filter)
Parameters: filter - string/object
Description: Deletes objects by filter.
Return value: Number of deleted objects