Database Management/Database Functions

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This lesson allows users to learn the basic functions of a database management system (DBMS).

Objectives and Skills[edit | edit source]

Objectives and skills for this lesson include:

Readings[edit | edit source]

  1. Wikipedia: Data integrity
  2. Wikipedia: Database transaction
  3. Wikipedia: Transaction log
  4. Wikipedia: Concurrency control
  5. Wikipedia: Record locking
  6. Wikipedia: Database encryption
  7. Wikipedia: Database security

Multimedia[edit | edit source]

  1. YouTube: DBMS Functions

Activities[edit | edit source]

  1. Activity on views for SQL Server[1]

Lesson Summary[edit | edit source]

  • Backups have two distinct purposes.
    • The primary purpose is to recover data after its loss, be it by data deletion or corruption.[1]
    • The secondary purpose of backups is to recover data from an earlier time, according to a user-defined data retention policy, typically configured within a backup application for how long copies of data are required.[2]
  • Backups represent a simple form of disaster recovery and should be part of any disaster recovery plan, backups by themselves should not be considered a complete disaster recovery plan.[3]
  • Database authorization explains privileges to users such as create role, grant role, revoke role and drop role.[4]
  • Control of data concurrency and data consistency is vital in a multiuser database. Data concurrency allows many users to access data at the same time. Data consistency means that each user sees a consistent view of the data, including visible changes made by the user's own transactions and transactions of other users.[5]
  • Database locking prevents multiple sessions from changing the same data at the same time.[6]
  • In a database system, a transaction might consist of one or more data-manipulation statements and queries, each reading and/or writing information in the database.[7]
  • Database security concerns the use of a broad range of information security controls to protect databases (potentially including the data, the database applications or stored functions, the database systems, the database servers and the associated network links) against compromises of their confidentiality, integrity and availability. It involves various types or categories of controls, such as technical, procedural/administrative and physical.[8]

Key Terms[edit | edit source]

ACID (atomicity, consistency, isolation, durability)
A set of properties of database transactions intended to guarantee data validity despite errors, power failures, and other mishaps.[9]
authentication
Verifying the identity of a computer system user.[10]
authorization
The function of specifying access rights/privileges to resources.[11]
backup
The copying into an archive file of computer data that is already in secondary storage so that it may be used to restore the original after a data loss event.[12]
backward recovery
Reading the log for problem transactions and applying the before images to undo their updates.[13]
catalog
Metadata in which definitions of database objects such as base tables, views (virtual tables), synonyms, value ranges, indexes, users, and user groups are stored.[14]
commit
Make a set of tentative changes permanent, marking the end of a transaction and providing durability to ACID transactions.[15]
concurrency control
Ensures that database transactions are performed concurrently without violating the data integrity of the respective databases.[16]
data dictionary
A read-only set of tables that contain all data definitions in a database.[17]
data integrity
The maintenance of, and the assurance of the accuracy and consistency of, data over its entire life-cycle.[18]
deadlock
A state in which each member of a group waits for another member, including itself, to take action, such as sending a message or more commonly releasing a lock.[19]
encryption
The process of obscuring information to make it unreadable without special knowledge, key files, or passwords.[20]
locking
Prevent destructive interactions when transactions access the same resource.[21]
metadata
The set of details on how the data in the database is stored.[22]
recovery
A process of salvaging (retrieving) inaccessible, lost, corrupted, damaged or formatted data from secondary storage, removable media or files, when the data stored in them cannot be accessed in a normal way.[23]
rollback
Undo a set of tentative changes, which returns the database to some previous consistent state.[24]
transaction
One or more data-manipulation statements and queries, each reading and/or writing information in the database.[25]
transaction log
A history of actions executed by a database management system used to guarantee ACID properties over crashes or hardware failures.[26]

See Also[edit | edit source]

References[edit | edit source]