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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.

500 Questions

What is difference between natural join equijoin and outer join?

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Asked by Wiki User

A natural join is a join that automatically matches columns with the same name in both tables. An equijoin is when the join condition is based on the equality of values in the specified columns. An outer join (left, right, or full) includes rows that do not have matching values in both tables, with NULL values filling in the gaps.

What is the difference between cartisean product and natural join operation?

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Asked by Wiki User

In a Cartesian product, every row in one table is combined with every row in the other table, resulting in a new table with all possible combinations. In a natural join, rows from two tables are combined based on common columns, resulting in a table that retains only the rows with matching values in those columns.

Does the size of a rubber band effect how far it will fly?

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Asked by Wiki User

Yes, the size of a rubber band can affect how far it will fly. Larger rubber bands typically have more elasticity and can store more energy when stretched, resulting in a longer flight distance compared to smaller rubber bands which may not have as much elasticity. However, other factors such as the force applied when releasing the rubber band and the aerodynamics of the object being launched also play a role in determining the flight distance.

What are the Building blocks of a database?

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Asked by Wiki User

Every database should contains values/datas represented in records(rows) and fields(columns). And records and fields stored in a table. So the main building blocks of a database is Table.

What does the name Noe mean?

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Asked by Wiki User

The name Noe is of Spanish, Portuguese, and French origin, derived from the Latin name Noah, meaning "rest" or "comfort." It is also a variation of the biblical name Noah, which means "to comfort" or "to rest."

As water is cooled what happens to the density?

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As water is cooled, its density increases until it reaches its maximum density at 4 degrees Celsius. Below 4 degrees Celsius, water begins to expand as it freezes, which is why ice is less dense than liquid water.

What is a field called in a physical database?

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Asked by Wiki User

In a physical database, a field is also called a column. It represents a specific piece of data that is stored in a database table, such as a name, age, or address. Each column typically has a data type that defines the kind of data it can hold.

How can you determine the curvature and Refractive Index of spectacle glass?

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Asked by Wiki User

The curvature of spectacle glass can be determined using a lensometer, which measures the curvature of the lens surface. The refractive index of spectacle glass can be determined by analyzing the way light passes through the lens and using equations that relate angles of light refraction to the refractive index of the material.

What is the full form of FASTA?

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FASTA stands for "Fast Alignment Search Tool". It is a software package used for searching nucleotide or protein databases with a query sequence.

What is the importance of database design in DBMS?

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Asked by Wiki User

A query is how you extract information from a database, which is one of the main reasons we have databases. There are other kinds of queries, such as ones to add, edit and delete data and manipulate data in other ways and do other things with tables, but the ones that extract information are the most used.

Block diagram of microwave communication link?

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Asked by Wiki User

A microwave communication link typically consists of a transmitter, a receiver, and an antenna at both ends. The transmitter converts the electrical signal into microwave signals, which are then transmitted through the antenna. The receiver at the other end captures these microwave signals through its antenna and converts them back into electrical signals for further processing. The link may also include devices such as amplifiers, filters, and antennas to enhance signal quality and transmission.

Molecular arrangement of solid liquid gas and plasma?

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Asked by Wiki User

In a solid, molecules are tightly packed together in a fixed lattice structure. In a liquid, molecules are more loosely packed and can move past each other. In a gas, molecules are far apart from each other and move freely. In a plasma, atoms are stripped of their electrons, resulting in a highly charged state where particles move rapidly and are electrically conductive.

What happens to the density of a cooled liquid?

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Asked by Wiki User

When a liquid is cooled, its molecules lose energy and move closer together, increasing the density of the liquid. This is because the decrease in temperature reduces the kinetic energy of the molecules, causing them to slow down and come closer to each other, leading to a more compact arrangement.

What is collation character set applicability table?

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Asked by Wiki User

A collation character set applicability table is used to determine which character sets can be used with a specific collation in a database. It specifies which character sets are compatible with a particular collation for sorting and comparison purposes. This table helps ensure that the data is stored and retrieved correctly based on the collation rules.

What are the entity integrity and referential integrity constraints Why is each considered important?

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Asked by Wiki User

Entity integrity ensures that each row in a table is uniquely identified by its primary key, preventing duplicate or null values in the key column. Referential integrity ensures that relationships between tables are maintained by enforcing foreign key constraints, preventing orphaned or invalid references between tables. Both constraints are important to maintain data accuracy, consistency, and reliability within a database system.

Why is a database considered to be self-describing?

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A database is considered self-describing because it contains metadata that describes its structure and organization. This metadata includes information about the tables, columns, data types, relationships, and other properties of the database. This allows users and applications to understand and interact with the database without needing external documentation.

What is the term plastic memory?

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"Plastic memory" refers to a phenomenon in which a material temporarily retains a deformation or shape after being subjected to stress, but eventually returns to its original shape once the stress is removed. This is often seen in certain types of plastics or materials that exhibit viscoelastic behavior.

What are the objectives of fact finding?

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The objectives of fact-finding include gathering accurate and reliable information, understanding the current situation or problem, identifying potential solutions, and making informed decisions based on evidence. It helps in uncovering the root cause of issues, determining the impact of different factors, and improving overall transparency in decision-making processes.

How much does android application development cost in general for enterprise app?

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Asked by JeffJohnsongp7031

Android application development cost varies a lot based on the features of the app and platforms associated. It can be commented after going through the detailed requirements. Professional android application development companies have ready framework for different type of apps and thus using that, may reduce the time and development cost. Better to share your scope with an app development company and get the absolute idea about pricing.

How do you explain characteristics of database approach?

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explain characteristic of database approach

Main Characteristics of the database approach0diggsdigg

- Self-describing nature of a database system.

a fundamental characteristic of the database approach is that the database system contains not only the database structure and constrains. this definition is stored in the system catalog.

A DBMS catalog stores the description of a particular database (e.g. data structures, types, and constraints)

the description is called meta-data

this allows the DBMS software to work with different database application.

- insulation between programs and data.

in traditional file processing, the structures of data files is embedded in the access programs, so many change to the structure of a file may require changing all programs that access this file.

by constraint, DBMS access programs do not require such changes in most cases. the structure of data files is stored in the DBMS catalog separately from the access programs.

we call this property program-data independence

program-data independence: allows changing data structures and storage organization without having to change the DBMS access programs.

- data abstraction.

the characteristic that allows program-data independence and program-operation independence is called data abstraction.

a data model is a type of data abstraction that is used to hide storage details and present the users with a conceptual view of the database.

- support of multiple views of the data.

each user may see a different view of the database, which describes only the data of interest to that user.

a view may be a subset of the database or it may contain virtual data that is derived from the database files but is not explicitly stored.

- sharing of data and multi-user transaction processing.

allowing a set of concurrent users to retrieve from and to update the database.

concurrency control within the DBMS guarantees that each transaction is correctly executed or aborted.

recovery subsystem ensures each completed transaction has its effect permanently recorded in the database.

OLTP (online Transaction Processing) is a major part of database applications. this allows hundreds of concurrent transactions to execute per second.

What does the term foreign key mean in databases?

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Asked by Wiki User

A foreign key is a field in a database table that is used to establish a relationship with another table. It ensures referential integrity by enforcing a link between two tables based on a matching key. This key is typically a primary key in the referenced table.

What are the three basic aspects of database security?

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Asked by Wiki User

The three basic aspects of database security are confidentiality (ensuring data is only accessible to authorized users), integrity (maintaining the accuracy and consistency of data), and availability (ensuring data is accessible when needed). These aspects help protect data from unauthorized access, tampering, and downtime.

What is relational state?

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Relational state is a concept in social psychology that refers to the emotional and psychological connection between individuals in a relationship. It involves the quality of interactions, feelings of closeness, and mutual understanding between people in a relationship. Strong relational states contribute to the overall satisfaction and well-being of individuals in a relationship.

What do mean by union compatibility?

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Asked by Wiki User

Union compatibility refers to the ability to combine two sets of data with the same structure and data types into a single dataset, usually by appending one set of data to another. Both sets must have the same number of columns, and those columns must have matching data types for union compatibility to be possible.