21.7. Property values
The REST API allows setting properties on nodes and relationships through direct RESTful operations. However, there are restrictions as to what types of values can be used as property values. Allowed value types are as follows:
- Numbers: Both integer values, with capacity as Java’s Long type, and floating points, with capacity as Java’s Double.
- Arrays of the basic types above.
There are two important points to be made about array values. First, all values in the array must be of the same type. That means either all integers, all floats, all booleans or all strings. Mixing types is not currently supported.
Second, storing empty arrays is only possible given certain preconditions. Because the JSON transfer format does not contain type information for arrays, type is inferred from the values in the array. If the array is empty, the Neo4j Server cannot determine the type. In these cases, it will check if an array is already stored for the given property, and will use the stored array’s type when storing the empty array. If no array exists already, the server will reject the request.
You can list all property keys ever used in the database. This includes and property keys you have used, but deleted.
There is currently no way to tell which ones are in use and which ones are not, short of walking the entire set of properties in the database.
List all property keys
[ "happy", "name1", "name", "name2", "non-existent", "cost", "since" ]