Metadata, Schema, and Catalog are very common names in database, so what are the meaning of them? 1: Metadata In short, metadata is the data about other data. Metadata is defined as the data providing information about one or more aspects of the data; it is used to summarize basic information about data which can make tracking and working with specific data easier. 2: Schema Schemas are analogous to directories at the operating system level, except that schemas cannot be nested. There are several reasons why one might want to use schemas: To allow many users to use one database without interfering with each other. To organize database objects into logical groups to make them more manageable. Third-party applications can be put into separate schemas so they do not collide with the names of other objects. 3: Catalog The system catalogs are the place where a relational database management system stores schema metadata, such as information about tables and columns, and internal bookkeeping...
The transient keyword in Java is used to indicate that a field should not be part of the serialization (which means saved, like to a file) process. Before understanding the transient keyword, one has to understand the concept of serialization. What is serialization? Serialization is the process of making the object's state persistent. That means the state of the object is converted into a stream of bytes to be used for persisting (e.g. storing bytes in a file) or transferring (e.g. sending bytes across a network). In the same way, we can use the deserialization to bring back the object's state from bytes. This is one of the important concepts in Java programming because serialization is mostly used in networking programming. The objects that need to be transmitted through the network have to be converted into bytes. For that purpose, every class or interface must implement the Serializable interface. It is a marker interface withou...