updateing one field in a table at a time in flutter - database

Question

i have made a user table in firebase firestore with multiple fields. and I am saving the data Onchange in text field when the user does any change. But when I change one field it changes all the field in the table and the other data gets altered. but I want to update single field when user updates it.
below is the code that i wrote to update in database -:
FirebaseFirestore firestore = FirebaseFirestore.instance;
void userinfo() async{
firestore.collection("users").doc('122345').update(
{
"name" : '${username.text}',
"Describe" : '${describe.text}',
"SchoolName" : '${school.text}',
"dob" : '${dob.text}',
"address" : '${address.text}',
},
). then((_){
print("success!");
});
}
TextFormField(
controller: username,
textInputAction: TextInputAction.next,
focusNode: fnOne,
autofocus: false,
maxLines: 1,
textAlign: TextAlign.center,
keyboardType: TextInputType.text,
decoration: InputDecoration(
enabled: true,
suffixIcon: Padding(
padding: EdgeInsets.only(top: 15, bottom: 15),
child: Icon(
Icons.edit,
color: Colors.pinkAccent,
),
),
labelText: Uname,
),
onChanged: (value) async{
value = username.text;
userinfo();
},
onSaved: (value){
value = username.text;
},
),
I am new to firebase can anyone help me with this please?

Answer 1

If you want to update only a subset of the document fields, the Map you pass to the update() method needs to contain only the corresponding elements.
For example, the following will update the SchoolName field and let the other fields unchanged:
FirebaseFirestore firestore = FirebaseFirestore.instance;
void userinfo() async{
firestore.collection("users").doc('122345').update(
{
"SchoolName" : '${school.text}',
},
). then((_){
print("success!");
});
}
It's up to you to define the Map according to the fields that are modified in the front-end.
Update following your comment:
You can do as follows to update only the desired field:
FirebaseFirestore firestore = FirebaseFirestore.instance;
void userinfo(fieldToUpdate, value) async{
var updateMap = new Map();
updateMap[fieldToUpdate] = value;
await firestore.collection("users").doc('122345').update(updateMap);
print("success!");
}
TextFormField(
controller: username,
// ...
onChanged: (value) async{
value = username.text;
userinfo('username', value);
}