Database Programming

One benefit of NIMS (National Incident Management System) is that it provides a standardized approach to incident management, enabling better coordination and communication between different agencies and organizations during emergencies.

"A data model is a collection of concepts that can be used to describe the structure of a database."

Data models can be broadly distinguished into 3 main categories-

1)high-level or conceptual data models (based on entities & relationships) - It provides concepts that are close to the way many users perceive data.

2)lowlevel or physical data models - It provides concepts that describe the

details of how data is stored in the computer.These concepts are meant for

computer specialist, not for typical end users.

3)representational or implementation data models (record-based,object-

0riented) - It provide concepts that can be understood by end users. These

hide some details of data storage but can be implemented on a computer

system directly.

Some of the disadvantages of dependency theory include oversimplification of complex economic relationships, neglect of internal factors contributing to underdevelopment, and criticism for offering limited solutions to address global inequality and poverty. Additionally, it has been criticized for its focus on historical colonial relationships at the expense of other critical factors influencing development.

1. Structured organization of data: Data is stored in tables with defined relationships.
2. Data integrity: Database systems enforce rules to maintain accuracy and consistency of data.
3. Query processing: Allows users to retrieve and manipulate data using SQL queries.
4. Concurrency control: Manages access to data to prevent conflicts in multi-user environments.

System data duplication, or denormalization, causes excess use of redundant storage, excess time processing queries, and possible inconsistency when de-normalized data is changed in one place but not the other. (Any one else have examples? Please enhance this answer. Thank you.)

Object Oriented Databases

Object oriented databases are also called Object Database Management Systems(ODBMS). Object databases store objects rather than data such as integers, strings or real numbers. Objects are used in object oriented languages such as Smalltalk, C++, Java, and others. Objects basically consist of the following:

Attributes - Attributes are data which defines the characteristics of an object. This data may be simple such as integers, strings, and real numbers or it may be a reference to a complex object.

Methods - Methods define the behavior of an object and are what was formally called procedures or functions.

Therefore objects contain both executable code and data. There are other characteristics of objects such as whether methods or data can be accessed from outside the object. We don't consider this here, to keep the definition simple and to apply it to what an object database is. One other term worth mentioning is classes. Classes are used in object oriented programming to define the data and methods the object will contain. The class is like a template to the object. The class does not itself contain data or methods but defines the data and methods contained in the object. The class is used to create (instantiate) the object. Classes may be used in object databases to recreate parts of the object that may not actually be stored in the database. Methods may not be stored in the database and may be recreated by using a class.

Comparison to Relational Databases

Relational databases store data in tables that are two dimensional. The tables have rows and columns. Relational database tables are "normalized" so data is not repeated more often than necessary. All table columns depend on a primary key (a unique value in the column) to identify the column. Once the specific column is identified, data from one or more rows associated with that column may be obtained or changed.

To put objects into relational databases, they must be described in terms of simple string, integer, or real number data. For instance in the case of an airplane. The wing may be placed in one table with rows and columns describing its dimensions and characteristics. The fusalage may be in another table, the propeller in another table, tires, and so on.

Breaking complex information out into simple data takes time and is labor intensive. Code must be written to accomplish this task.

Object Persistence

With traditional databases, data manipulated by the application is transient and data in the database is persisted (Stored on a permanent storage device). In object databases, the application can manipulate both transient and persisted data.

When to Use Object Databases

Object databases should be used when there is complex data and/or complex data relationships. This includes a many to many object relationship. Object databases should not be used when there would be few join tables and there are large volumes of simple transactional data.

Object databases work well with:

CAS Applications (CASE-computer aided software engineering, CAD-computer aided design, CAM-computer aided manufacture)

Multimedia Applications

Object projects that change over time.

Commerce

Object Database Advantages over RDBMS

Objects don't require assembly and disassembly saving coding time and execution time to assemble or disassemble objects.

Reduced paging

Easier navigation

Better concurrency control - A hierarchy of objects may be locked.

Data model is based on the real world.

Works well for distributed architectures.

Less code required when applications are object oriented.

Object Database Disadvantages compared to RDBMS

Lower efficiency when data is simple and relationships are simple.

Relational tables are simpler.

Late binding may slow access speed.

More user tools exist for RDBMS.

Standards for RDBMS are more stable.

Support for RDBMS is more certain and change is less likely to be required.

ODBMS Standards

Object Data Management Group

Object Database Standard ODM6.2.0

Object Query Language

OQL support of SQL92

How Data is Stored

Two basic methods are used to store objects by different database vendors.

Each object has a unique ID and is defined as a subclass of a base class, using inheritance to determine attributes.

Virtual memory mapping is used for object storage and management.

Data transfers are either done on a per object basis or on a per page (normally 4K) basis.

A database is made up of related Schemas and Tables. A single database can have multiple schemas and each schema can have multiple tables inside it. All of these can be related to one another using referential constraints like foreign keys.

Data mining involves uncovering insights and patterns from large datasets to help make informed business decisions. It plays a crucial role in database systems by extracting valuable information from the stored data and discovering hidden patterns, trends, and relationships. This process helps businesses identify opportunities, predict future outcomes, and optimize decision-making.

Advantages:

Cheap, cost effective, efficient with time.

Disadvantages:

Can lead to system failure, risky, would need to be updated frequently (in early stages) for system maintenance etc

Procedures in a database are stored code segments, which can be executed. This is a good way of holding any business logic in a single place. A procedure could be very simple and return the value of the square of two number, or be very complicated, and perform a lot of data validation before inserting data into a table or updating a table for example.

Tables or charts are just an easy way to organize data. So in terms of a presentation a table makes it easier for the audience to understand it. If you didn't have a data table, chart, or graph what would you have? random numbers on the board?

SQL is the language used to access a database. So if you want to work with databases, especially to query or manipulate data, then it is important that you learn SQL. Even if you use other APIs, you will still need to use SQL queries.

This database collects and stores data on patient follow-up to track health outcomes and trends over time. By analyzing the data, public health professionals can identify patterns, assess interventions, and make informed decisions to improve public health outcomes.

An ER diagram of a library database management system helps to keep all aspects of running a library organized. The diagram should include the books and publishers, as well as members of the library and who has checked out which books.

Data isolation refers to the concept of keeping data separated and protected from unauthorized access or modification within a database management system. It ensures that each transaction in the database is independent and operates as if no other transactions are occurring simultaneously, preventing interference and maintaining data integrity. Data isolation is crucial for ensuring the consistency, reliability, and security of the database.

Representation and education are the two main functions of museums. Museums represent cultural heritage and history through their collections and exhibitions, providing a platform for learning and understanding. Additionally, they serve as educational institutions by offering interpretation and context to help the public engage with and appreciate the artifacts and stories on display.

In database we store data however the can be redundant. Redundancy means repetitive data that is taking extra storage space . So to reduce or prevent the storage space we should eliminate redundancy or just reduce it.

A row in a database represents a single record or entry within a table. It contains a set of related data fields that are organized into columns, with each column representing a different attribute or variable associated with that record. Rows are used to store and retrieve information in a structured manner within a database.

Data refers to raw facts or figures that are collected, while information is data that has been processed or organized in a way that gives it meaning or context. In essence, data is the foundation on which information is built.

Logical data independence refers to the key feature of database management system that helps maintain data integrity and the overall effectiveness of the data usage. It is very important as it allows for the modification of the conceptual schema without disturbing the external schema.

In a database, a field is any area that can be filled in with different kinds of data that are relating to one thing. For example, in a database to do with population, there is likely to be an age field.