Firestore query documents startsWith a string

Firestore query documents startsWith a string

In Firestore, you can query documents where a specific field starts with a particular string by using the orderBy and startAt or startAfter methods in combination with a where clause. Firestore does not have a direct "startsWith" operator, but you can achieve the same result by structuring your query appropriately.

Here's how you can query documents where a specific field starts with a string:

import com.google.api.core.ApiFuture; import com.google.cloud.firestore.*; public class FirestoreQueryStartsWith { public static void main(String[] args) throws Exception { Firestore db = FirestoreOptions.getDefaultInstance().getService(); // Define the collection reference CollectionReference collection = db.collection("your_collection_name"); // Specify the prefix you want to match String prefix = "abc"; // Create a query Query query = collection.whereGreaterThanOrEqualTo("your_field_name", prefix) .whereLessThan("your_field_name", prefix + "\uf8ff"); // Execute the query ApiFuture<QuerySnapshot> querySnapshot = query.get(); // Iterate through the documents that start with the specified prefix for (QueryDocumentSnapshot document : querySnapshot.get().getDocuments()) { System.out.println("Document ID: " + document.getId()); System.out.println("Field Value: " + document.get("your_field_name")); } } }

In this example:

  1. Replace "your_collection_name" with the name of the collection you want to query.

  2. Replace "your_field_name" with the name of the field you want to check for the prefix.

  3. Specify the prefix variable with the string you want to match.

  4. Create a query using whereGreaterThanOrEqualTo and whereLessThan conditions to filter documents where the field value is greater than or equal to the prefix and less than a value that includes all characters (prefix + "\uf8ff").

  5. Execute the query using query.get().

  6. Iterate through the documents returned by the query and process them as needed.

This query will retrieve documents where the specified field's value starts with the provided prefix.

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