What is Avro Schema

Avro schema generally used to define the data schema for a record's value. This schema describes the fields allowed in the value, along with their data types. We can apply a schema to the value portion of an Oracle NoSQL Database record using Avro bindings. These bindings are used to serialize values before writing them, and to deserialize values after reading them. The usage of these bindings requires our applications to use the Avro data format, which means that each stored value is associated with a schema.

The use of Avro schemas allows serialized values to be stored in a very space-efficient binary format. Each value is stored without any metadata other than a small internal schema identifier, between 1 and 4 bytes in size. One such reference is stored per key-value pair. In this way, the serialized Avro data format is always associated with the schema used to serialize it, with minimal overhead. This association is made transparently to the application, and the internal schema identifier is managed by the bindings supplied by the AvroCatalog class. The application never sees or uses the internal identifier directly.

To describe an Avro schema, you create a JSON record which identifies the schema, like this:

{
     "type": "record",
     "namespace": "com.example",
     "name": "FullName",
     "fields": [
       { "name": "first", "type": "string" },
       { "name": "last", "type": "string" }
     ]
}