Table of Contents
- 1 What does a data dictionary show?
- 2 What is a data dictionary document?
- 3 Why do you need a data dictionary?
- 4 What is stored in data dictionary?
- 5 What is the use of data dictionary?
- 6 What are the types of metadata a data dictionary stores?
- 7 What is the difference between active and passive data dictionary?
- 8 What is the difference between active and self updating data dictionary?
What does a data dictionary show?
A Data Dictionary is a collection of names, definitions, and attributes about data elements that are being used or captured in a database, information system, or part of a research project. A Data Dictionary also provides metadata about data elements.
What is a data dictionary document?
A data dictionary, or metadata repository, as defined in the IBM Dictionary of Computing, is a “centralized repository of information about data such as meaning, relationships to other data, origin, usage, and format”. …
Why do you need a data dictionary?
Data dictionaries are used to provide detailed information about the contents of a dataset or database, such as the names of measured variables, their data types or formats, and text descriptions. A data dictionary provides a concise guide to understanding and using the data.
What information is not provided by a data dictionary?
the size of the disk storage device.
What is the purpose of data dictionary?
Data dictionaries are used to provide detailed information about the contents of a dataset or database, such as the names of measured variables, their data types or formats, and text descriptions.
What is stored in data dictionary?
A data dictionary contains: The definitions of all schema objects in the database (tables, views, indexes, clusters, synonyms, sequences, procedures, functions, packages, triggers, and so on) How much space has been allocated for, and is currently used by, the schema objects. Default values for columns.
What is the use of data dictionary?
What are the types of metadata a data dictionary stores?
Relational databases store and provide access not only data but also metadata in a structure called data dictionary or system catalog….There are several sorts of metadata consistent with their uses and domain.
- Technical Metadata –
- Business Metadata –
- Descriptive Metadata –
- Operational Metadata –
What information does the data dictionary contain?
The data dictionary in general contains information about the following − Names of all the database tables and their schemas. Details about all the tables in the database, such as their owners, their security constraints, when they were created etc. Physical information about the tables such as where they are stored and how.
What is data dictionary in DBMS?
Data Dictionary consists of database metadata. It has records about objects in the database. Data Dictionary consists of the following information − Constraints of a table i.e. keys, relationships, etc. An example of Data Dictionary can be personal details of a student − The following is the data dictionary for the above fields −
What is the difference between active and passive data dictionary?
A passive data dictionary is maintained separately to the database whose contents are stored in the dictionary. That means that if the database is modified the database dictionary is not automatically updated as in the case of Active Data Dictionary. So, the passive data dictionary has to be manually updated to match the database.
What is the difference between active and self updating data dictionary?
So, the data dictionary is automatically updated by the database management system when any changes are made in the database. This is known as an active data dictionary as it is self updating. This is not as useful or easy to handle as an active data dictionary.