# Write Operations

Documents can be inserted into a collection using insert() method. It takes one or multiple Document objects as input parameter. It returns a WriteResult object.

If the document has a NitriteId already in it's _id field, then it will be used as a unique key to identify the document in the collection. Otherwise, a new NitriteId will be generated and inserted into the document.

If any of the field is already indexed in the collection, then the index will be updated accordingly.

Document doc = Document.createDocument("firstName", "John")
    .put("lastName", "Doe")
    .put("age", 30)
    .put("data", new byte[] { 1, 2, 3, 4, 5 });

WriteResult result = collection.insert(doc);

Document doc1 = Document.createDocument("firstName", "John")
    .put("lastName", "Doe")
    .put("age", 30)
    .put("data", new byte[] { 1, 2, 3, 4, 5 });

Document doc2 = Document.createDocument("firstName", "Jane")
    .put("lastName", "Doe")
    .put("age", 25)
    .put("data", new byte[] { 1, 2, 3, 4, 5 });

WriteResult result = collection.insert(doc1, doc2);

• If the document is null, then it will throw a ValidationException.
• If the document contains invalid value in it's _id field, then it will throw a InvalidIdException.
• If there is another document with the same _id value in the collection, then it will throw a UniqueConstraintException.
• If a field of the document is unique indexed and it's value violates the index constraint, then it will throw a UniqueConstraintException.

WriteResult contains the result of a write operation. It contains the following information:

• Number of documents affected by the write operation. You can get this value using getAffectedCount() method.
• List of NitriteId of the documents affected by the write operation. The WriteResults implements Iterable<NitriteId> interface. So you can iterate over the WriteResult to get the NitriteId of the documents affected by the write operation.

Documents can be updated in a collection using update() method. There are several overloaded version of update() method. You can update a single document or multiple documents at a time. You can also update a document using a filter.

You can update a single document using update() method. It takes a Document object as input parameter. It returns a WriteResult object. The document must contain a valid NitriteId in it's _id field. The document must not be null.

Document doc = Document.createDocument("_id", existingDoc.getId())
    .put("age", 30);

WriteResult result = collection.update(doc);

You can upsert a single document using update() method. It takes a Document object as the first input parameter. It takes a boolean value as the second input parameter. If the second input parameter is true, then it will insert the document if it does not exist in the collection. Otherwise, it will update the document if it exists in the collection. It returns a WriteResult object. The document must not be null.

Document doc = Document.createDocument("_id", existingDoc.getId())
    .put("lastName", "Doe")
    .put("age", 30)
    .put("data", new byte[] { 1, 2, 3, 4, 5 });

WriteResult result = collection.update(doc, true);

You can update multiple documents using a filter. It takes a Filter object as the first input parameter. It takes a Document object as the second input parameter. It returns a WriteResult object. The document must not be null or empty.

If the filter result matches multiple documents, then all the documents will be updated.

Document update = Document.createDocument("_id", existingDoc.getId())
    .put("firstName", "Jane");

WriteResult result = collection.update(where("firstName").eq("John"), update);

You can update multiple documents using a filter and options. It takes a Filter object as the first input parameter. It takes a Document object as the second input parameter. It takes a UpdateOptions object as the third input parameter. It returns a WriteResult object. The document must not be null or empty.

UpdateOptions is a class that contains several options for update operation. It has the following options:

• insertIfAbsent: If this option is true, then it will insert the document if it does not exist in the collection. Otherwise, it will update the document if it exists in the collection.
• justOnce: If this option is true, then it will update only the first document matched by the filter. Otherwise, it will update all the documents matched by the filter.

Document update = Document.createDocument("_id", existingDoc.getId())
    .put("firstName", "Jane");

UpdateOptions updateOptions = new UpdateOptions();
updateOptions.insertIfAbsent(true);
updateOptions.justOnce(true);

WriteResult result = collection.update(where("firstName").eq("John"), update, updateOptions);

Documents can be removed from a collection using remove() method. There are several overloaded version of remove() method. You can remove a single document or multiple documents at a time using a filter.

You can remove a single document using remove() method. It takes a Document object as input parameter. It returns a WriteResult object. The document must contain a valid NitriteId in it's _id field. The document must not be null.

Document doc = Document.createDocument("_id", existingDoc.getId());

WriteResult result = collection.remove(doc);

You can remove multiple documents using a filter. It takes a Filter object as the input parameter. It returns a WriteResult object.

If the filter result matches multiple documents, then all the documents will be removed.

WriteResult result = collection.remove(where("firstName").eq("John"));

You can remove multiple documents using a filter and options. It takes a Filter object as the first input parameter. It takes a boolean value as the second input parameter. If the second input parameter is true, then it will remove only the first document matched by the filter. Otherwise, it will remove all the documents matched by the filter. It returns a WriteResult object.

WriteResult result = collection.remove(where("firstName").eq("John"), true);