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Database Design
Database design is the process of creating a detailed data model of a database. It is the next step after requirement gathering and before coding begins. A good database design can save a lot of time during the database development.
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The problems will fall into general classes: problems for the patient, problems for the service provider, problems for the product support team, problems for the vendor to name a few. The risk attached to system design can be mitigated using a design review process. What happens if design limitations are discovered after the fact? You under go the expense of upgrading the design. However, attempting to anticipate all usage needs up front can also be counter-productive. Release a design that meets the identified need but allowing for some expansion, and then as use increases to the point that design limitations are approached, then you release an enhanced design using customer experience as a guide. Having an active customer user group or community helps proactively identify areas for enhancements to manage the design limitation problems feared.
Object-oriented databases use small, reusable chunks of software called objects. The objects themselves are stored in the object-oriented database. Each object consists of two elements: 1) a piece of data (e.g., sound, video, text, or graphics), and 2) the instructions, or software programs called methods, for what to do with the data. Part two of this definition requires a little more explanation. The instructions contained within the object are used to do something with the data in the object. For example, test scores would be within the object as would the instructions for calculating average test score.
Object-oriented databases have two disadvantages. First, they are more costly to develop. Second, most organizations are reluctant to abandon or convert from those databases that they have already invested money in developing and implementing. However, the benefits to object-oriented databases are compelling. The ability to mix and match reusable objects provides incredible multimedia capability. Healthcare organizations, for example, can store, track, and recall CAT scans, X-rays, electrocardiograms and many other forms of crucial data.
Example of a field that might be used in a database about students?
A database is a collection of information about a particular group, for example students. The person creating the database must decide what fields they need. For a student database, you'd definitely need each student's name, address, city, state, and parent's telephone number. And, depending on your needs, you might want to list at least 1 parent's name. The rest of the fields would depend on the purpose of your database.
Let's say it's a 10th grade science class in which students must do 5 experiments, create a poster for the Table of Elements, prepare 2 class presentations, and write 2 papers (1 being 8 pages and 1 being 10 pages). In addition, you must record which students returned a signed parent's permission slip in order to attend a science Expo in Washington, D.C., plus you wanted to keep track of which students are entered into the Science Fair. Therefore, you'd have at least 13 fields for the items I listed (including the 5 separate fields for experiment1, experiment2, experiment3, etc.)
List the advantages and disadvantages of OODBMS?
The advantages of OODBMS include; extensibility, expressive query language, improved performance, ability to handle many data types, enriched modelling capabilities and support for long transactions. The disadvantages are as follows; lack of standards, lack of experience, competition, compromised encapsulation due to query optimization and lack of a universal data model.
What database software is typically used when Windows is the operating system?
There are many databases (Database server) solutions available for the Windows Operating system. The choice made is depending about many factors; such as: Scalability requirements Intellectual capital within the firm (Which produce the IT people know how to work with). Existing system platforms being used Capital available for building and maintaining a solution Some examples of database solutions would be: (Commercial Solutions) Microsoft SQL Server Oracle Microsoft Access (Open Source Solutions) MySQL Postgress SQL More about the solutions available: Microsoft SQL This is the most popular solutions. MS SQL is idea in most all situations however Oracle has a scale advantage in VERY heavy transaction environments where millions of records will be inserted on an ongoing basis. MS SQL server has a free desktop version as well as various licensed models to fit a wide spectrum of installation needs; which includes clustering, etc. Oracle Oracle is known to be a very expensive solution and is typically installed in very large installations. Additionally Oracle is often selected in a MIXED OS environment. As an example a firm may have some Unix Oracle installations and Windows OS installations. (The free alternatives) MySQL MySQL as come a long way however it is still not truly a database engine on the backside. MySQL is more a flat data stored with an interface program (not a server based product) that allows for the accessing of the data through SQL program code. Some will argue that MySQL is very good while most SQL programmers would strongly advice against it. This is not a debate that we will enter into here. MySQL has been around for a long time and independent programmers and small software companies have implemented it successfully. MySQL is closest to MSSQL in its SQL language deployment. This being said it is a viable option for a SQL deployment however popular opinion might suggest other routes. PostGress SQL is often related to Oracle in its SQL language deployment (more like Oracle than MSSQL). While I do not have hands on experience with Oracle OR PostGress my understanding from highly trusted resources is that PostGress is a very strong open source option. Postgress is stable, adheres to ANSI SQL standards and is a true database engine. Given my limited knowledge on Postgress and Oracle overall I would say that Postgress is a strong alternative however research should be done to insure that this is the right option for you. Postgress SQL is another free
According to the Smart Card Alliance what is the maximum distance a contactless smart card operates?
25 to 35 ft
What is a field in a database?
In a doctor's database, there would be several fields. The fields could contain the patient's name, address, telephone or mobile number, their Name,Age,Date of birth,allergies, and the doctor's name. Each thing would have a field of its own. So the patient's name and the doctor's name would be in two separate fields. When the data is viewed, the fields would appear as columns within the data. The fields need to be defined before any data is put in. So you would specify that you want a field for a phone number and a field for a doctor's name etc. when you are designing the database.
Key words:
Field: A field is in a database, it contains important information.
Advantage and disadvantage of sparse index over the dence index?
Sparse advantage, less storage space required
Dense advantage faster since each index key is directly linked to a record key
What 4 goals that a firm may have beside profit maximization?
A company may have many goals besides profit maximization: To capture a certain percentage of market share. To produce the highest quality product. To have the highest level of customer satisfaction. To have the highest level of employee satisfaction. To have the lowest percentage of warranty repairs/product failures. To be the industry leader in product innovation. To be the industry leader in technology. To be environmentally friendly (green).
What is grahic design and how is it different from product design?
Graphic Design usually applies to the labels or printed material on the packaging of the product as well as the print and web advertising for that product. Product design is the structural design of the product itself. For example, while a product designer would design the shape and structure of a new mobile phone, the graphic designer might do the artwork for the box that the mobile phone will be shipped in as well as magazine ads for the phone.
QBE (or query-by-example) is often a quick method of creating simple SQL queries, especially by users who are not particularly SQL-savvy. Instead of having to remember specific SQL syntax, the user builds the query by selecting tables and fields from a display and entering WHERE and GROUP BY clause specifics in a fill-in-the-box manner.
What are differences between data types numeric and non numeric?
Numeric data are data that can be quantify. i.e age, e.t.c While Non-numeric data are data that cannot be quantify but can be categorise. Such as colour, name e.t.c
A database manager is a computer program (or programs) that manages database information. Most database programs can be purchased or obtained from many places and installed on a computer. That makes it software.
If the database program is part of and supplied with the computer vendors system, than it is system software.
It is possible to securely store the database program in a type of memory where its location is fixed and not changeable using normal programming methods. That would make it firmware.
If the database software is implemented in the actual computer machinery and not changeable without replacing or changing computer components, it would be hardware.
What should a IT student understand the most in class?
First of all an IT student should pay peak attention in his/her class. As most important part of IT lectures is programming. Programming languages are nothing theoretical rather conceptual and practical. So, one should understand the flow of language, examples, code exactly then only he/she will be learn the subject. If anything is missed then later part will be difficult to learn.
Microsoft uses this to make sure that the version of Windows you are using is genuine, before they offer you free software. You can check if the version of Windows you are using is genuine by right clicking 'My Computer' or 'Computer' on the start menu.
The purpose of a Design Authority in an IT project is to provide direction and momentum to a project.
A design authority (DA) is a person or a group of persons
- that knows concretely how the project must proceed (vision)
- that has the authority to make binding decisions (mandate)
- that has the professional knowledge and skill to make material choices based on substantive argumentation (knowledge)
- that has the power to settle discussions and implement choices on a daily basis (leadership)
- that motivates participants to perform beyond their own expectations (charisma).
My role models for a design authority are Calatrava, Rem Koolhaas en Willem Dudok. In this definition, the DA is the substantive and artistic director. In a large project, it is a team, in which authorized experts cover all aspects from business to IT. A DA can only work well in total openness and cocreation.
The absence of a DA in a large IT project yields confusion and uncertainty among project participants on their task and role in the project. As a result, they will hide behind procedures, project plans, deadlines and budgets. This situation occurs when only the process is managed and the content is not.
The metaphor is a cart (=the project) that is pulled by a team of horses (=project participants). The job of the driver (the DA) is to give direction and speed.
Without direction, the horses will pull in all directions. This costs energy (=money) but does not result in any movement of the cart. If you make the horses pull harder, the cart will still not go anywhere even though the team is spending more energy...
System maintence could mean anything from updating or upgrading your computer to checking for viruses and defragging your computer.
What are the roles of database and database administrators?
A database is a storage that contains data. To manage data in the database different roles are assigned . One such role is of a DBA that is database administrator that is responsible for managing the database.
A database stores data and manages data. It allows people to enter data and get information from the data in the form of queries or reports.
A database administrator looks after the maintenance of the database, including things like the design, testing, security etc. He services the needs of users that have to access the database.
Why is anomalies required in database?
Anomalies are not required in a database. An anomaly is a inconsistency or a problem. A well designed database should not have any anomalies. If there are some, they can cause problems for the users and for the reliability and efficiency of the database.
Differentiate logical and physical database?
After all business requirements have been gathered for a proposed database, they must be modeled. Models are created to visually represent the proposed database so that business requirements can easily be associated with database objects to ensure that all requirements have been completely and accurately gathered. Different types of diagrams are typically produced to illustrate the business processes, rules, entities, and organizational units that have been identified. These diagrams often include entity relationship diagrams, process flow diagrams, and server model diagrams. An entity relationship diagram (ERD) represents the entities, or groups of information, and their relationships maintained for a business. Process flow diagrams represent business processes and the flow of data between different processes and entities that have been defined. Server model diagrams represent a detailed picture of the database as being transformed from the business model into a relational database with tables, columns, and constraints. Basically, data modeling serves as a link between business needs and system requirements. Two types of data modeling are as follows: * Logical modeling * Physical modeling If you are going to be working with databases, then it is important to understand the difference between logical and physical modeling, and how they relate to one another. Logical and physical modeling are described in more detail in the following subsections. Logical modeling deals with gathering business requirements and converting those requirements into a model. The logical model revolves around the needs of the business, not the database, although the needs of the business are used to establish the needs of the database. Logical modeling involves gathering information about business processes, business entities (categories of data), and organizational units. After this information is gathered, diagrams and reports are produced including entity relationship diagrams, business process diagrams, and eventually process flow diagrams. The diagrams produced should show the processes and data that exists, as well as the relationships between business processes and data. Logical modeling should accurately render a visual representation of the activities and data relevant to a particular business. The diagrams and documentation generated during logical modeling is used to determine whether the requirements of the business have been completely gathered. Management, developers, and end users alike review these diagrams and documentation to determine if more work is required before physical modeling commences. Typical deliverables of logical modeling include * Entity relationship diagrams
An Entity Relationship Diagram is also referred to as an analysis ERD. The point of the initial ERD is to provide the development team with a picture of the different categories of data for the business, as well as how these categories of data are related to one another. * Business process diagrams
The process model illustrates all the parent and child processes that are performed by individuals within a company. The process model gives the development team an idea of how data moves within the organization. Because process models illustrate the activities of individuals in the company, the process model can be used to determine how a database application interface is design. * User feedback documentation Physical modeling involves the actual design of a database according to the requirements that were established during logical modeling. Logical modeling mainly involves gathering the requirements of the business, with the latter part of logical modeling directed toward the goals and requirements of the database. Physical modeling deals with the conversion of the logical, or business model, into a relational database model. When physical modeling occurs, objects are being defined at the schema level. A schema is a group of related objects in a database. A database design effort is normally associated with one schema. During physical modeling, objects such as tables and columns are created based on entities and attributes that were defined during logical modeling. Constraints are also defined, including primary keys, foreign keys, other unique keys, and check constraints. Views can be created from database tables to summarize data or to simply provide the user with another perspective of certain data. Other objects such as indexes and snapshots can also be defined during physical modeling. Physical modeling is when all the pieces come together to complete the process of defining a database for a business. Physical modeling is database software specific, meaning that the objects defined during physical modeling can vary depending on the relational database software being used. For example, most relational database systems have variations with the way data types are represented and the way data is stored, although basic data types are conceptually the same among different implementations. Additionally, some database systems have objects that are not available in other database systems. Typical deliverables of physical modeling include the following: * Server model diagrams
The server model diagram shows tables, columns, and relationships within a database. * User feedback documentation Database design documentation Understanding the difference between logical and physical modeling will help you build better organized and more effective database systems.
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What is difference between natural join and outer join?
A natural join allows the database to attempt to determine relationships on behalf of the programmer by comparing column names and joining on those fields. It only shows columns once when they are duplicated in the tables, and operates on rows that contain matches in both tables (an "inner join").
A outer join will show results for any matching rows, even if one of the two tables does not contain a matching record. In those events, the empty table's fields will be "null", since no match was found. Depending on the type of outer join, either table a will always have a record, table b will always have a record, or either table may not have a record (but at least one record is required per row to generate a row).
What is used of computer in hosptle?
These are the main usage of computer in hospital:
- Record a large amount of data
- Less chances of lost of data
- For operation purposes
