Access Multiple Nodes in Firebase Database - ios

Question

I am having a hard time pulling all my data from one of my nodes in my firebase database.
Here is how the node looks like in Firebase:
Considerations
-MEdUNZwVrsDW3dTrE6N
Company Description:
Company Image:
Company Name:
Decision Date:
Start Date:
Users
B2Z4DlZ8RucvEQhz2NSUkquqc5P2
Compensation:
PostNumber:
StoryNumber:
Under users there are going to be multiple people with different values for the compensation, post number, and storynumber. I have each user having a node called "user-considerations" that tags the unique id of the consideration each user is attached on and places it under their UID and tags a 1 next to it as the value. I am trying to access each specific user's info along with the other info in the node. Here is my code that I am using to call the information along with the struct I a using to capture the information:
STRUCT:
import UIKit
class ConsiderationInfo: NSObject {
var companyName: String?
var companyImage: String?
var companyDescription: String?
var decisionDate: String?
var startDate: String?
var compensation: String?
var postNumber: String?
var storyNumber: String?
}
CODE FOR OBSERVING INFO:
func updateConsiderationsArray() {
let uid = Auth.auth().currentUser?.uid
let ref = Database.database().reference().child("user-considerations").child(uid!)
ref.observe(.childAdded, with: { (snapshot) in
let considerationId = snapshot.key
let considerationReference = Database.database().reference().child("Considerations").child(considerationId)
considerationReference.observe(.value, with: { (snapshot) in
if let dictionary = snapshot.value as? [String: AnyObject] {
let considerationInfo = ConsiderationInfo()
//self.setValuesForKeys(dictionary)
considerationInfo.companyName = dictionary["Company Name"] as? String
considerationInfo.companyImage = dictionary["Company Image"] as? String
considerationInfo.companyDescription = dictionary["Company Description"] as? String
considerationInfo.decisionDate = dictionary["Decision Date"] as? String
considerationInfo.startDate = dictionary["Start Date"] as? String
self.considerationsInfo.append(considerationInfo)
self.considerationName.append(considerationInfo.companyName!)
self.filteredConsiderations.append(considerationInfo.companyName!)
self.considerationCollectionView.reloadData()
}
}, withCancel: nil)
})
}
I am trying to access the information under the user specific node, i.e. the specific user's compensation post number and story number. I am unaware of how to access all of this to append the struct.
Here is the node with the user-considerations:

Answer 1

As it sits, I am really not seeing anything super wrong with the code but there are few things that could be changed to make it more streamlined.
I would first change the Consideration Info class to make it more self contained. Add a convenience initializer to handle a firebase snapshot directly with some error checking.
class ConsiderationInfo: NSObject {
var companyName = ""
convenience init(withSnapshot: DataSnapshot) {
self.init()
self.companyName = withSnapshot.childSnapshot(forPath: "Company Name").value as? String ?? "No Company Name"
}
}
I would also suggest removing the .childAdded and .observe events unless you specifically want to be notified of future changes. Use .value and .observeSingleEvent instead. Keeping in mind that .childAdded iterates over each node in your database one at a time - .value reads them in all at the same time. If there is a limited amount of data, .value works well.
func updateConsiderationsArray() {
let fbRef = Database.database().reference()
let uid = Auth.auth().currentUser?.uid
let ref = fbRef.child("user_considerations").child(uid)
ref.observeSingleEvent(of: .value, with: { snapshot in
let allUidsSnap = snapshot.children.allObjects as! [DataSnapshot]
for uidSnap in allUidsSnap {
let considerationId = uidSnap.key
let considerationReference = fbRef.child("Considerations").child(considerationId)
considerationReference.observeSingleEvent(of: .value, with: { snapshot in
let considerationInfo = ConsiderationInfo(withSnapshot: snapshot)
self.considerationArray.append(considerationInfo)
// update your collectionView
})
}
})
}
What I am doing in the above is reading in the single node from user_considerations, which looks like this according to your quuestion
user_considerations
some_user_uid
a_user_uid
a_user_uid
and then mapping each child user to an array to maintain order
let allUidsSnap = snapshot.children.allObjects as! [DataSnapshot]
and then iterating over each, getting the uid (the key) of each node and getting that nodes data from the Considerations node.