Databases

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Database - a database is, a place that we store an organized collection of data. collection of tables.

Atribute of db:
-store
-access
-manipulate
-retrive

Database consist of:
-storage
-memory
-processor
-software

 Database Managment Systems - the collection of programs that enable the users to access the database amd manipulate, retrive data to the users.


Types of DBMS:

 a) Hierarchical DBMS

- this type of DBMS users the parent-child relationship for stroing the data. It stores the data like a tree with nodes and branches. The registry usage of Windows XP is a good example for this DBMS type.

-but this type of DBMS is used so rarely nowadays. so no need to go further for this type.


 b) Network DBMS

-RDM Server is an example of this type.

-This type uses many to many relations. But this type generally results complex database structures.

-so it is not a frequently used DBMS model.

 c) Relational DBMS

-this type is the most used DBMS nowadays.

-the Oracle Database, MYSQL, MSSQL and many others use this type of database management systems.

-Unlike the network DBMS, relational DBMS does not support many to many relationship. Relational DBMS have some entities, basically means tables, and we establish some relations between these entities.

-This type of DBMS have pre-defined types and you can store only these types in it.

d) Object-Relational Database Managment Systems

- this type supports storing new data types. Because you can have your own objects and each object is a type in it . So you can have your own type in it. The object here have attributes, means the data, and the methods that define what to do with this data.

-this is also a useful database managment system and maybe the most known example of that type is PostgreSQL.




row (records)

cloumns

table


Role of DBA
- the primary role of a DBA is to protect the organization's data
-installation, configuration, upgrade and migration
-backup and recovery
-database security
-storage and capacity planning
-performance monitoring and tuning
-troubleshooting
-high availability



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