CSC 121 As I See it 007

Distinguish the Difference/Relationships between folder,file,records, and fields:

1. Folder
- contains records, and in which each record is specified in a single line.
2. File
-stores information
3. Record
-An item or collection of data
4. Fields
-is a place where you can store data.


Relationship:

-Information in the database is generally stored in several different files. Each file consists of series of records. Each records consists of several fields, with each field containing an individual data item.

- an individual database as a whole has a lot of related files with related records on it. A single record is composed of related fields in which each of that field has related attributes. Inside each field, there are related data which constitute the field. The data is the last constituent of the whole system. It is the fundamental among all since when data is grouped and related to each other it will constitute a field then a record then into a file and finally into a database.

-fields, records, files and objects optimized to deal with very large amounts of data stored on a permanent structure.

CSC 121 As I See It 006

Differentiate all the basic and alternative database models :

Hierarchical

This is a tree structured model for a database. It requires that the application knows about the physical relationships between entities. The structure is rigid. Hierarchical structures were widely used in the early mainframe database management systems. This structure allows one 1:N relationship between two types of data and is very efficient to describe many relationships in the real world; recipes, table of contents, ordering of paragraphs/verses, any nested and sorted information. However, the hierarchical structure is inefficient for certain database operations when a full path is not also included for each record.

ex. IMS is a hierarchical database.

Network

An extension of the tree into a lattice so that multiple relationships can be supported. This model is inflexible, requiring significant changes if relationships change. The network model is a variation on the hierarchical model, to the extent that it is built on the concept of multiple branches (lower-level structures) emanating from one or more nodes (higher-level structures), while the model differs from the hierchical model in that branches can be connected to multiple nodes. The network model is able to represent redundancy in data more efficiently than is the hierarchical model.

ex. CODASYL and IDMS is a network database.

Relational

This model is based on relational algebra and encompasses the rules developed by Codd. Most of the databases in commercial use now are relational. The model is flexible and extensible. It makes database management systems more independent of any particular application. Three key terms are used extensively in relational database models: relations, attributes, and domains. A relation is a table with columns and rows. The named columns of the relation are called attributes, and the domain is the set of values the attributes are allowed to take.

ex. Sybase, Oracle, Ingres.

Object

Object databases address the need to store more complex data types than are supported by the relational model. These databases attempt to bring the database world and the application programming world closer together, in particular by ensuring that the database uses the same type system as the application program. This aims to avoid the overhead of converting information between its representation in the database (for example as rows in tables) and its representation in the application program. At the same time, object databases attempt to introduce the key ideas of object programming into the world of databases
Object databases suffered because of a lack of standardization: although standards were defined by ODG, they were never implemented well enough to ensure interoperability between products. Nevertheless, object databases have been used successfully in many applications: usually specialized applications such as engineering databases or molecular biology databases rather than mainstream commercial data processing

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10 examples of DBMS Software:

1. Oracle Database by Oracle Corporation
2. Adaptive Server Enterprise (ASE) by Sybase Corporation's
3.MySQL by MySQL AB
4. FileMaker from FileMaker Inc.
5. Informix by IBM
6. Microsoft Office Access, previously known as Microsoft Access, from Microsoft
7. PostgreSQL under a BSD-style license
8. OpenEdge Advanced Business Language, by Progress Software Corporation (PSC).
9. CSQL developed in sourceforge.net.
10. Visual FoxPro by Microsoft

"Oracle Database System"

An Oracle database system comprises at least one instance of the application, along with data storage. An instance comprises a set of operating-system processes and memory-structures that interact with the storage.

The Oracle RDBMS stores data logically in the form of tablespaces and physically in the form of data files. Tablespaces can contain various types of memory segments; for example, Data Segments. Extents comprise groups of contiguous data blocks. Data blocks form the basic units of data storage. At the physical level, data-files comprise one or more data blocks, where the block size can vary between data-files.

Oracle database management track its computer data storage with the help of information stored in the SYSTEM tablespace. The SYSTEM tablespace contains the data dictionary — and often (by default) indexes and clusters.

Each Oracle instance uses a System Global Area or SGA — a shared-memory area — to store its data and control-information. Oracle stores information here about the logical and physical structure of the database.

CSC 121 As I see it 004

Correlate the following:

1. Data and Database

Information in the database is generally stored in several different files. Each file consists of series of records. Each records consists of several fields, with each field containing an individual data item. From this sentence, we can say that in a database, data are an important factor in which composes database. Data is important since in database is a huge collection of data that were organized according to their data types.

2. System and Management

System is the software program of the computer that coordinates the fuction of each hardware components of the computer. The system software works like a traffic inforcer inside the CPU since in every instructions given by the user, the system software coordinate all the hardware to accomplish the task. On the other hand, management is somewhat like managing the a whole integrated processing to accomplish a task. On this, all the hardware are helping each ohter to achieve what the user wants the computer to do. without the system software, the whole hardware components will be useless since the system software do all the coordination of the hardware components for them to work.

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1. Why input data?

-We need to input data in order to process it by the CPU. When users input data, the user and the machine are interconnected to each other.
-We input data so that the computer program be completed.

2. why process data?

-Processing data means to overview the data inputed by the user and obtaining a meaningful information from the data.
-We process data to gain a factual information to be used in our daily lives.
After processing the data, it will become a new powerful information that can be used instantly.

3. Output for what?

- Output so that we can see the hard copies or back-up copies of what we make in the computer.
- To obtain the result of the processng of data.
- To display the outcome of the desired information from that data input by the user.