当我发布问题时，我写了一些例程来帮助自动化这个过程。我没有发布它们，因为它们有点初级，我希望有一个优雅的基于 Firestore 的解决方案。因为这样的解决方案还没有，这里是我写的函数。
简而言之，我们有重命名字段、添加字段或删除字段的功能。要重命名字段，根据数据类型使用不同的函数。也许有人可以更好地概括这一点？下面的函数是：
-
add_field：在集合的所有文档中添加一个字段。
-
delete_field：删除集合的所有文档中的字段。
-
rename_*_field：重命名集合的所有文档中包含特定数据类型 (*) 的字段。这里我包含了字符串、整数和日期的示例。
添加字段：
public void add_field (final String key, final Object value, final String collection_ref) {
FirebaseFirestore.getInstance().collection(collection_ref).get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
WriteBatch batch = db.batch();
for (DocumentSnapshot document : task.getResult()) {
DocumentReference docRef = document.getReference();
Map<String, Object> new_map = new HashMap<>();
new_map.put(key, value);
batch.update(docRef, new_map);
}
batch.commit();
} else {
// ... "Error adding field -> " + task.getException()
}
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
// ... "Failure getting documents -> " + e
}
});
}
删除字段：
public void delete_field (final String key, final String collection_ref) {
FirebaseFirestore.getInstance().collection(collection_ref).get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
WriteBatch batch = db.batch();
for (DocumentSnapshot document : task.getResult()) {
DocumentReference docRef = document.getReference();
Map<String, Object> delete_field = new HashMap<>();
delete_field.put(key, FieldValue.delete());
batch.update(docRef, delete_field);
}
// Commit the batch
batch.commit().addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
// ...
}
});
} else {
// ... "Error updating field -> " + task.getException()
}
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
// ... "Failure getting notices -> " + e
}
});
}
重命名字段：
public void rename_string_field (final String old_key, final String new_key, final String collection_ref) {
FirebaseFirestore.getInstance().collection(collection_ref).get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
WriteBatch batch = db.batch();
for (DocumentSnapshot document : task.getResult()) {
DocumentReference docRef = document.getReference();
String old_value = document.getString(old_key);
if (old_value != null) {
Map<String, Object> new_map = new HashMap<>();
new_map.put(new_key, old_value);
Map<String, Object> delete_old = new HashMap<>();
delete_old.put(old_key, FieldValue.delete());
batch.update(docRef, new_map);
batch.update(docRef, delete_old);
}
}
// Commit the batch
batch.commit().addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
// ...
}
});
} else {
// ... "Error updating field -> " + task.getException()
}
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
// ... "Failure getting notices ->" + e
}
});
}
public void rename_integer_field (final String old_key, final String new_key, final String collection_ref) {
FirebaseFirestore.getInstance().collection(collection_ref).get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
WriteBatch batch = db.batch();
for (DocumentSnapshot document : task.getResult()) {
DocumentReference docRef = document.getReference();
int old_value = document.getDouble(old_key).intValue();
Integer ov = old_value;
if (ov != null) {
Map<String, Object> new_map = new HashMap<>();
new_map.put(new_key, old_value);
Map<String, Object> delete_old = new HashMap<>();
delete_old.put(old_key, FieldValue.delete());
batch.update(docRef, new_map);
batch.update(docRef, delete_old);
}
}
// Commit the batch
batch.commit().addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
// ...
}
});
} else {
// ... "Error updating field -> " + task.getException()
}
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
// ... "Failure getting notices -> " + e
}
});
}
public void rename_date_field (final String old_key, final String new_key, final String collection_ref) {
FirebaseFirestore.getInstance().collection(collection_ref).get()
.addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
@Override
public void onComplete(@NonNull Task<QuerySnapshot> task) {
if (task.isSuccessful()) {
WriteBatch batch = db.batch();
for (DocumentSnapshot document : task.getResult()) {
DocumentReference docRef = document.getReference();
Date old_value = document.getDate(old_key);
if (old_value != null) {
Map<String, Object> new_map = new HashMap<>();
new_map.put(new_key, old_value);
Map<String, Object> delete_old = new HashMap<>();
delete_old.put(old_key, FieldValue.delete());
batch.update(docRef, new_map);
batch.update(docRef, delete_old);
}
}
// Commit the batch
batch.commit().addOnCompleteListener(new OnCompleteListener<Void>() {
@Override
public void onComplete(@NonNull Task<Void> task) {
// ...
}
});
} else {
// ... "Error updating field -> " + task.getException()
}
}
})
.addOnFailureListener(new OnFailureListener() {
@Override
public void onFailure(@NonNull Exception e) {
// ... "Failure getting notices -> " + e
}
});
}