arangosh> db.test.ensureIndex({ type: "hash", fields: [ "a" ] });
{
"id" : "test/15971",
"type" : "hash",
"fields" : [
"a"
],
"selectivityEstimate" : 1,
"unique" : false,
"sparse" : false,
"isNewlyCreated" : true,
"code" : 201
}
arangosh> db.test.save({ a : 1 });
{
"_id" : "test/15974",
"_key" : "15974",
"_rev" : "15974"
}
arangosh> db.test.save({ a : 1 });
{
"_id" : "test/15978",
"_key" : "15978",
"_rev" : "15978"
}
arangosh> db.test.save({ a : null });
{
"_id" : "test/15981",
"_key" : "15981",
"_rev" : "15981"
}