DocumentMutation.setOrReplace()

Operations Performed

Verifies that a field at the specified path exists.

If the field exists, changes its value to the specified value, even if the data type of the specified value differs from the data type of the current value.
If the field does not exist, creates the field and gives it the specified value.

NOTE: If an application tries to set a new value in an array and gives the value an index higher than (current largest index) + 1, then the value is given the index (current last index) + 1. For example, suppose that an application tries to set a value at index 5 in an array for which the current largest index is 2. MapR-DB assigns the value an index of 3 when inserting the value into the array.

Example of Setting and Replacing Scalar Values

Original document

{ 
  "_id" : "000001",
  "a" : {
         "b" : 1 
         }
}

Example code for the set

  public DocumentMutation buildDocumentMutation() {
    return MapRDB.newDocumentMutation()
      .setOrReplace("a", ImmutableMap.of(
        "b", "newString",
        "c", 2));
  }

  public void update(String tablePath, DocumentMutation mutation, String _id) {
    try(Table table = MapRDB.getTable(tablePath)) {
      table.update(_id, mutation);
    }
  }

Parameter	Description
`_id`	The value of the document's `_id` field.
`tablePath`	The path of the table in the MapR file system. See Table Paths.

Revised document

{ 
  "_id" : "000001",
  "a" : {
         "b" : "newString",
         "c" : 2
         }
}

Permissions Required

The readAce and writeAce permissions on the volumes where the JSON tables that contain the documents are located. For information about how to set permissions on volumes, see Setting/Modifying Whole Volume ACEs.
writeperm on the field, if it exists. See How to Obtain readperm or writeperm on a Field.
readperm and writeperm on the field, if it exists and contains an array. See How to Obtain readperm and writeperm on a Field.
writeperm on the parent field, if the specified field does not exist. See How to Obtain readperm or writeperm on a Field.

Link to Javadoc

DocumentMutation

IMPORTANT: If a DocumentMutation object modifies a field two or more times, only the final operation on that field is applied.

Example One

table.update() in the last line fails with error code 22:

DBDocument doc = MapRDB.newDocument()
        .set("int", 100)
        .set("date", new Date(1000))
        .set("string", "a string");

table.insertOrReplace("doc1", doc);

// Set different fields
DocumentMutation mutation = MapRDB.newDocumentMutation();
mutation.setOrReplace("string", 1000);
mutation.set("string", 2000);

table.update("doc1", mutation);

Example Two

This code results in the document {"string":"a string add3"}, rather than the document {"string":"a string add1 add2 add3"}.

DBDocument doc = MapRDB.newDocument()
        .set("string", "a string");

table.insertOrReplace("doc1", record);

DocumentMutation mutation = MapRDB.newDocumentMutation();
mutation.append("string", " add1");
mutation.append("string", " add2");
mutation.append("string", " add3");

table.update("doc1", mutation);