Let's say you have a class person like the following: public class Person implements java.io. # Deserializes a string from the database to an attribute value.Though most of the users have already given the answer, but I would like to add an example for those who need it in order to explain the idea: # Serializes an attribute value to a string that will be stored in the database. Serialize the preferences attribute using a custom coder class Rot13JSON
Circular references inside the array/object you are serializing will also be stored. You can even serialize () arrays that contain references to itself. Serialize the preferences Hash using YAML class User < ActiveRecord::Base serialize () handles all types, except the resource -type and some object s (see note below). Serialize the preferences attribute using JSON class User < ActiveRecord::Base Internal binary representations of data also vary accordingly in every. Computer systems may vary in their hardware architecture, OS, addressing mechanisms. Otherwise, the default will be nil.Įxamples Serialize the preferences attribute using YAML class User < ActiveRecord::Base Data serialization is the process of converting data objects present in complex data structures into a byte stream for storage, transfer and distribution purposes on physical devices. If this option is not passed, the previous default value (if any) will be used. :default - The default value to use when no value is provided. The technical definition is a bit more fun. The dump method may return nil to serialize the value as NULL.
When transmitting data or storing them in a file, the data are required to be byte strings, but complex objects are seldom in this format. Serialization means to convert an object into that string, and deserialization is its inverse operation (convert string -> object). Unseralization can use std::istream::peek() to check for the 'N' tag. E.g., if the first character of a serialized object is always a digit, use a non-digit like 'N' to mean a NULL pointer. The attribute value must respond to to_json.Ĭustom coder - The attribute value will be serialized using the coder's dump(value) method, and will be deserialized using the coder's load(string) method. JSON is a format that encodes objects in a string. Otherwise, if the first serialized character in an object has a known range, use something outside that range. JSON - The attribute value will be serialized as JSON. Hash - The attribute value will be serialized as YAML, but an empty Hash will be serialized as NULL.
The attribute value must respond to to_yaml.Īrray - The attribute value will be serialized as YAML, but an empty Array will be serialized as NULL. May be one of the following:ĭefault - The attribute value will be serialized as YAML. ParametersĪttr_name - The name of the attribute to serialize.Ĭlass_name_or_coder - Optional. There is no need to use serialize in this case.įor more complex cases, such as conversion to or from your application domain objects, consider using the ActiveRecord::Attributes API. For instance: json and jsonb types in PostgreSQL will be converted between JSON object/array syntax and Ruby Hash or Array objects transparently. Keep in mind that database adapters handle certain serialization tasks for you.
The serialization format may be YAML, JSON, or any custom format using a custom coder class. Note: The XRP Ledger uses the same serialization format to represent. If you have an attribute that needs to be saved to the database as a serialized object, and retrieved by deserializing into the same object, then specify the name of that attribute using this method and serialization will be handled automatically. After signing, you must re-serialize the transaction with the TxnSignature field included.
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