What is database design?
The overall structure of a database is what we call database design. Before creating a database one must design a database that different anomalies. Anomalies like redundancy and must come up with a optimized database design for efficient use.
Design of the database (Database Design) refers to a given application environment, optimize the structure of the database, the database and applications, which can efficiently store data to meet the application needs of various user information needs and processing requirements). At www. myelibrary.net.In you can clearly understand what is the database design.
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This is a very broad question. I'll try to present different areas for you to consider when designing a database.. 1. What is the database program and what is the OS it will …reside on? 2. What is the scope of the database? Small (100 tables), medium (500 tables), large (1000+ tables and maybe a Terabyte of data?) 3. What type of data needs to be stored? 4. You'll need to know the hierarchy, related data (to make relationships between the tables), nature of the data within the tables to properly size the tables for future growth.. Now, if you don't have all the up-front information, you can always create the database with what you do know. However, realize that later you may have to restructure, recreate the tables larger and copy the data or it may be easier just to recreate the database. If you need to do this, you can export the data if you have any that needs saved. If on the same node, you can do this table to table or by flat files. Table to table, you will have to disable auditing and any constraints, they reenable when finished. If you insert by flat files, it is faster and you will not have to disable.. There is a lot to designing, updating and maintaining a database.
hmm, I start to think what am will doing with database, usually I write firts all my idea on a paper and when it ready to build, I use my database application.
A properly designed database could mean many things. Essentially, it all depends on what kind of database a user / webmaster / etc is looking for. A table (In a database) shou…ld have a correct number of collumns. Traditionally, the names of these collumns should be lowercased (But doesn't have to be). A table (In a database) should have a primary key collumn. A primary key is used to uniquely identify each "row". No two rows cannot have the same primary key - it is unacceptable - therefore no two rows can be mixed up. This also cures many problems people may find in the future. In website database table values, "yes" and "no" should be replaced with boolean values: TRUE or FALSE, or even 1 and 0. When working with sensitive information, it's a good option to encrypt it somehow - You never know; someone may hack into the system unnexpectedly. Passwords are good examples of values that should be encrypted. There are a number of many things that will make a database effective and smooth, but it is ultimately up to the creator and modifier of the database to decide.
A database designer is a person who specifies how a database records are stored, accessed and related to make sure there is adequate performance!
Depends on the design tool, there are MANY design tools and they all have some similar characteristics and some unique ones as well.\n. \nFor the most part design tools help …you design a physical database using a visual representation.\n. \nie: Graphics that you can drag around, and connect that will result in the code required to generate the resulting database.
Designers design the original database. That is an extensiveprocess, including working out the structures, doing up specialdiagrams, choosing the correct software and computer…s to use andother things. Finally the database will be created. The job of theadministrator is to look after the database. The administratorlooks after things like security, backups, providing services tothe users, updating data and maintaining the database. Thedesigner's role is mainly before the database comes into use andthe administrator looks after the database when it does come intouse.
By rigorously collecting business requirements, understanding the desired end result as well as the potential expansion / change directions. By considering future plans an arc…hitect can design around these possibilities; properly staging the environment for these future plans. At times it may make more sense and be little to no additional work to invoke some of these plans from the beginning. A great example of this would be an application that maintains data for a customer facing portal. lets say that today a company is looking for a simple portal. Plans down the road however would include the ability for a customer to view items that they have looked at in the past. Now for marketing reasons you may want to track this anyway; but assuming that you do not...... With these future plans in mind you may track the historical information from day one. Although the coding is not present to utilize the information it can be of great use later. In this example imagine being able to announce this new capability to your customers; say 6 months after launching the portal... AND being able to inform your customers that they can also view all prior activity (Prior to the service actually being offered or even programmed). this would be made possible because forethought and planning took place that resulted in the retention of the information that would later be needed.
Table design in Microsoft Access can be performed by right clicking the table name in navigation view (column that runs down the left hand side of Access that is headed 'All A…ccess Objects' by default) or by clicking the "geometry set" icon on the far left hand side of the ribbon called "View" with the table actually open. In Design view you can create and rename fields and assign a "Data Type" to represent the type of data being entered into each field such as Text, Date, Number etc. Hope this helps.
Determine the purpose of the database - This helps prepare for the remaining steps. . Find and organize the information required - Gather all of the types of information to… record in the database, such as product name and order number. . Divide the information into tables - Divide information items into major entities or subjects, such as Products or Orders. Each subject then becomes a table. . Turn information items into columns - Decide what information needs to stored in each table. Each item becomes a field, and is displayed as a column in the table. For example, an Employees table might include fields such as Last Name and Hire Date. . Specify primary keys - Choose each table's primary key. The primary key is a column that is used to uniquely identify each row. An example might be Product ID or Order ID. . Set up the table relationships - Look at each table and decide how the data in one table is related to the data in other tables. Add fields to tables or create new tables to clarify the relationships, as necessary. . Refine the design - Analyze the design for errors. Create tables and add a few records of sample data. Check if results come from the tables as expected. Make adjustments to the design, as needed. . Apply normalization - Apply the data normalization rules to see if tables are structured correctly. Make adjustments to the tables
Three key issues we have to consider: â¢ Data Allocation : where are data placed? Data should be stored at site with "optimal" distribution. â¢ Fragmentation : relat…ion may be divided into a number of sub-relations (called fragments) , which are stored in different sites. â¢ Replication : copy of fragment may be maintained at several sites.
A well designed database will be normalized to the third normal form (3NF). The normal forms that are generally required to have a well designed database are First Normal Form… (1NF), Second Normal Form (2NF), and Third Normal Form (3NF). 1NF states that each table has no dependency on top-to-bottom record ordering, left-to-right column ordering, no duplicate rows, and each column/row intersection contains exactly one value. For example, a column "Customer Name" is a bad idea; instead, consider "First Name" and "Last Name", since those are individual elements of a customer's full name. 2NF adds to 1NF by stating that each non-key column depends on the entire concatenated key (if the key is a composite primary key). For example, the description of an item would not belong in a table that stores items that were ordered; instead, it should be on the item table itself. Finally, 3NF builds upon 2NF (and thus 1NF) by stating that data should not depend on a non-key attribute. For example, the customer's name should not appear in an order invoice table; the correct way to store this data would be in a customer table, with the order invoice table containing a reference to the customer table. There are further forms (see any popular search engine for details), but those are generally considered more academic than practical in nature. In most cases, a database that fully conforms to 3NF will likely satisfy 4NF, 5NF, and 6NF, although there is no specific guarantee of that.
A database or systems designer will do it. They could also haveother roles like being an analyst or a database administrator.Whoever is designing a database may work with peop…le in some ofthose other jobs, particularly when it is a very large system. Ifit is a small database, then it is easy to design and somebody witha bit of knowledge of databases can design and create one.
The logic structure is independent of any kind of data model,in the practical application, the general database used by theenvironment has given (such as SQL Server or Oracel …or MySQL. Due to the current use of the database basically is relational database, so the first thing to the E-R diagram into relation model, and then according to the characteristics andlimitations of specific DBMS conversion for the specificsupport of DBMS data model, the final optimization
When you create a relation (Relationship) within an DBMS you are establishing a relationship of a field in one table to a field another table. Example. We Have a table Custo…mers CustomerID FirstName LastName StatusID The sample fields above are for table Customers Now the StatusID is an INT field and we need to define a relationship between this field and the StatusID column in the Status table StatusID StatusDescription isActive Above are examples of the Status table. To complete our example here we will create a relationship that looks as follows: Customers->StatusID ---> Status->StatusID
As the name implies, a database designer develops both the logicaland physical design of the database. For hierarchical databases,they define the parent-child relationships an…d in relationaltables, the relations between tables. They also often developvalidation rules, constraints and the like.
Database designers are a type of software engineer that specializesin databases. Therein they will investigate the requirements of theend user platform, design the system inte…rface to create, edit andreport on stored data , design user interfaces, design reports,structure and develop an optimized platform.
Centralized design is one of the two major methods of designing a networked database, the other being distributed design. In a centralized design, all the database table schem…a and the data reside in one place where all of the users access it (i.e., central to the users.) Conversely, a distributed design replicates the schema in multiple places and segments the data amongst the multiple sets of tables. Each group of users accesses a particular distributed set of tables with the data relevant to their group. This improves data security and retrieval time for the users at the cost of increased complexity of database maintenance and backup.