What is Database?
- It is a organized collection of data
- It is simply one or more table of data that are organised and stored in a very structured way.
- It is collection of interrelated data stored with minimum redundancy to serve many users Efficiently so the users can perform variety of operation on DBMS.
What are the basics of database?
Relational databases support the following set of properties:
- Atomicity — This means a transaction can either execute completely or not at all.
- Consistency — Once a transaction has been committed, the data must conform to the given schema.
- Isolation — Concurrent transactions execute separately from each other.
- Durability — The ability of the DB to recover from an unexpected system failure or outage. ...
What is the main purpose of database?
- To develop software applications In less time.
- Data independence and efficient use of data.
- For uniform data administration.
- For data integrity and security.
- For concurrent access to data, and data recovery from crashes.
- To use user-friendly declarative query language.
What database should I use?
- MySQL is probably the most popular for websites.
- PostgreSQL is another great open-source RDBMS.
- Oracle and Microsoft SQL Server are commercial, but powerful databases. Stack Overflow is a good example of a website that uses MS SQL Server.
- MongoDB is the most popular NoSQL database, and there have been some successful websites that use it. ...
What are the main features of a database?
The processing power of a database allows it to manipulate the data it houses, so it can:
- Sort
- Match
- Link
- Aggregate
- Skip fields
- Calculate
- Arrange
What is database concepts and its types?
Definition of Database or Database meaning: A database is a systematic collection of data. They support electronic storage and manipulation of data. Databases make data management easy. DBMS stands for Database Management System. We have four major types of DBMSs namely Hierarchical, Network, Relational, Object- ...
What are the basic concepts of database management system?
Database Management Systems (DBMS) are software systems used to store, retrieve, and run queries on data. A DBMS serves as an interface between an end-user and a database, allowing users to create, read, update, and delete data in the database.
Why is database concept important?
A database is typically designed so that it is easy to store and access information. A good database is crucial to any company or organisation. This is because the database stores all the pertinent details about the company such as employee records, transactional records, salary details etc.
What are the basic database operations?
The basic operations are INSERT, UPDATE, SELECT and DELETE. Although the target database system is SQL Server Database, the same techniques can be applied to other database systems because the query syntax used is standard SQL that is generally supported by all relational database systems.
What are the 4 types of database management system?
Types of DBMSRelational database.Object oriented database.Hierarchical database.Network database.
How many types of database are there?
Four types of database management systems hierarchical database systems. network database systems. object-oriented database systems.
What are the five uses of database?
Uses of database management system are as follows:On-Demand Online Video Streaming.Social Gaming.Personal Cloud Storage.Telecommunication.Finances.
What are the 4 main objects of a database?
While Microsoft Access is made up of seven components, this text will focus on the main objects: tables, forms, queries and reports. Together, these objects allow users to enter, store, analyze and compile data in various ways.
What is database example?
Databases often store information about people, such as customers or users. For example, social media platforms use databases to store user information, such as names, email addresses and user behavior. The data is used to recommend content to users and improve the user experience.
What are the characteristics of database?
What are the Characteristics of DBMS?Real World Entity.Self Explaining Nature.Atomicity of Operations (Transactions)Concurrent Access without Anomalies.Stores Any Kind of Structured Data.Integrity.Ease of Access (The DBMS Queries)SQL and No-SQL Databases.More items...•
What is database and its operations?
Database operations is the development, maintenance, and support of structured data to maximize the value of data across the organization. This function includes database support and data technology management.
What is operational database example?
Operational databases are used to store, manage and track real-time business information. For example, a company might have an operational database used to track warehouse/stock quantities.
What are the different operations of functions performed in database?
Functions of DBMSData Dictionary Management. ... Data Storage Management. ... Data transformation and presentation. ... Security Management. ... Multi User Access Control. ... Backup and Recovery Management. ... Data Integrity Management. ... Database Access Languages and Application Programming Interfaces.More items...
What are the additional basic operations in SQL?
The SQL operations union, intersect, and except operate on relations and correspond to the mathematical set-theory operations ∪, ∩, and −.
What is a database?
A database is a tool for collecting and organizing information. Databases can store information about people, products, orders, or anything else. Many databases start as a list in a word-processing program or spreadsheet. As the list grows bigger, redundancies and inconsistencies begin to appear in the data. The data becomes hard to understand in list form, and there are limited ways of searching or pulling subsets of data out for review. Once these problems start to appear, it's a good idea to transfer the data to a database created by a database management system (DBMS), such as Access.
What is a database in Access?
A computerized database is a container of objects. One database can contain more than one table. For example, an inventory tracking system that uses three tables is not three databases, but one database that contains three tables. Unless it has been specifically designed to use data or code from another source, an Access database stores its tables in a single file, along with other objects, such as forms, reports, macros, and modules. Databases created in the Access 2007 format (which is also used by Access, 2016, Access 2013 and Access 2010) have the file extension .accdb, and databases created in earlier Access formats have the file extension .mdb. You can use Access 2016, Access 2013, Access 2010, or Access 2007 to create files in earlier file formats (for example, Access 2000 and Access 2002-2003).
How to get the most flexibility out of a database?
To get the most flexibility out of a database, the data needs to be organized into tables so that redundancies don't occur. For example, if you're storing information about employees, each employee should only need to be entered once in a table that is set up just to hold employee data.
What is the function of a query?
Queries can perform many different functions in a database. Their most common function is to retrieve specific data from the tables. The data you want to see is usually spread across several tables, and queries allow you to view it in a single datasheet. Also, since you usually don't want to see all the records at once, queries let you add criteria to "filter" the data down to just the records you want.
What is a field in a table?
Fields correspond to the columns in the table . For example, you might have a table named "Employees" where each record (row) contains information about a different employee, and each field (column) contains a different type of information, such as first name, last name, address, and so on.
How to describe records and fields?
Another way to describe records and fields is to visualize a library's old-style card catalog. Each card in the cabinet corresponds to a record in the database. Each piece of information on an individual card (author, title, and so on) corresponds to a field in the database.
Can you program buttons in a database?
However, most database users prefer to use forms for viewing, entering, and editing data in the tables. You can program command buttons to determine which data appears on the form, open other forms or reports, or perform a variety of other tasks.
What is the number of tuples or rows in a relation called?
Cardinality: The number of tuples or rows in a relation is termed as cardinality.
What are the advantages of using a database?
Advantages of Using Database 1 Database minimizes data redundancy to a great extent. 2 The database can control the inconsistency of data to a large extent. 3 Sharing of data is also possible using the database. 4 Database enforce standards. 5 The use of Databases can ensure data security. 6 Integrity can be managed using the database.
What is relation in data?
Relation: In general, a relation is a table, i.e., data is arranged in rows and columns. A relation has the following properties:
Why should a database be accurate?
It should be accurate so that diverse applications with different data requirements can employ the data.
What can control the inconsistency of data to a large extent?
The database can control the inconsistency of data to a large extent.
How many levels of abstraction are there in a database?
As the database may be viewed through three levels of abstraction, any change at any level can affect other levels' schemas. Since the database keeps on growing, then there may be frequent changes at times. This should not lead to redesigning and re-implementation of the database. The concepts of data independence prove beneficial in such types of contexts.
What are the columns and fields of a table called?
Attributes: The columns or fields of a table is termed as Attributes.
What is DBMS in database?
5. Z Introduction • DBMS stands for Database Management System. • DBMS is a software system for creating, organizing and managing the database. • It provides an environment to the user to perform operations on the database for creation, insertion, deletion, updating and retrieval of data.
What is data in a computer?
6. Z What is a Data? • Data: A collection of raw facts and figures. • Raw material that can be processed by any computing machine. • A collection of facts from which conclusions may be drawn. • Data can be represented in the form of: numbers and words which can be stored in computer’s language.
Why is a database made up of related data?
A database is made up of related data because the individual items of data have a connection of some sort. An address book, an encyclopaedia and a telephone directory are examples of paper-based manual databases. However, it is more common to talk about computerised databases. Computerised databases have several advantages over manual databases.
What is database creation?
Database creation involves using software to define and build the structures to hold the data. In a database file the data is structured in a particular way.
What is a computerised database?
A computerised database is a collection of related data stored in one or more computerised files in a manner that can be accessed by users or computer programs.
What is sequential data file?
In a sequential data file the data the records are still in series but they are stored in order, using one of the records in the database. This makes if much easier to locate a particular record using an algorithm such as a binary sort.
Why is a database persistent?
A database is persistent because the data and structures are stored in secondary storage, even when the applications that use the data are no longer running. A database is organised because the data is stored in a very structured way, using tables, records and fields so that users and data handling applications can easily add, delete, edit, ...
What is a simple query?
Simple query – looking for data in one field only (for example – for example a user of a car showroom database could run a simple query to find out how may Toyota cars there are in stock).
What is a flat file database?
This database FILE would contain just one table and is known as a flat-file database. There are a number of limitations to such databases and a relational database which contains multiple linked tables offers many advantages.
How is organized data stored efficiently?
The most efficient way to store data is with the help of a relational database. A relational database consists of 3 high-level components:
What are columns in relational databases called?
Columns may also be known as attributes, fields, or features. Rows may also be called records, entries, or tuples.
How are relational databases different from Excel/Google Spreadsheets?
On a very small scale, spreadsheet programs can work well. But the minute you start to think about scalability, security, and usability, spreadsheets no longer suffice.
What is a key in a table?
Keys allow unique identification for all rows in the table. Without keys there would be no way to differentiate between entries that have identical information in their columns. Two people in a table can have the same names and birthdays and without a unique key, it will be hard to differentiate between them and can lead to unnecessary confusion.
What is database storage?
A database can be thought of as a kind of electronic filing cabinet; it contains digitized information (“data”), which is kept in persistent storage of some kind, typically on magnetic disks. Users can insert new information into the database, and delete, change, or retrieve existing information in the database, by issuing requests or commands to the software that manages the database—which is to say, the database management system (DBMS for short). Note: Throughout this book, I take the term user to mean either an application programmer or an interactive user [ 2] or both, as the context demands.
What is table S in a spreadsheet?
They’re meant to be understood as follows: Table S represents suppliers under contract.
Why is data independence important?
Now, the reason we might want to change the way the database is physically stored and accessed is almost always performance; and the fact that we can make such changes without having to change the way the database looks to the user means that existing application programs, queries, and the like can all still work after the change. Very importantly, therefore, data independence means protecting existing investment— investment in user training, in existing applications, and in existing database designs (among other things).
What does SNO mean in a contract?
Table S represents suppliers under contract. Each supplier has one supplier number (SNO), unique to that supplier; one name (SNAME), not necessarily unique (though the sample values shown in Figure 1-1 do happen to be unique); one status value (STATUS); and one location (CITY). Note: In the rest of this book I’ll abbreviate “suppliers under contract,” most of the time, to just suppliers.
Why are security controls important?
Security controls are needed to ensure that user requests are legitimate, in the sense that the user in question is requesting an operation he or she is allowed to carry out on data he or she is allowed to access. In the case of the suppliers-and-parts database, for example, some users might not be allowed to see supplier status values; others might not be allowed to see suppliers at all; others might be allowed to see suppliers in London but not in other cities; others might be allowed to retrieve supplier information but not to update it; and so on. In a nutshell, users must be limited to performing only those operations they’re allowed to perform. Note: Security is important, of course, but further details of security controls are mostly beyond the scope of this book (except for a brief mention in Chapter 7 ).
What is table SP?
Table SP represents shipments —it shows which parts are shipped, or supplied, by which suppliers. Each shipment has one supplier number (SNO); one part number (PNO); and one quantity (QTY). Also, there’s at most one shipment at any given time for a given supplier and given part, and so the combination of supplier number and part number is unique to any given shipment.
What does table P mean?
Table P represents kinds of parts. Each kind of part has one part number (PNO), which is unique; one name (PNAME); one color (COLOR); one weight (WEIGHT); and one location where parts of that kind are stored (CITY). Note: In the rest of this book I’ll abbreviate “kinds of parts,” most of the time, to just parts.
What is concurrency control?
Concurrency control and locking is the mechanism used by DBMSs for the sharing of data. Atomicity, consistency, and isolation are achieved through concurrency control and locking.
What is a database management system?
Introduction. A database management system (DBMS) is system software for creating and managing databases. The DBMS provides users and programmers with a systematic way to create, retrieve, update and manage data.
What is page locking?
In this situation, all the data on a specific page are locked. A page is a common unit of storage in computer systems and is used by all types of DBMSs. In this figure, each rectangle represents a page. Locking for objects is on the left and page locking for relational tuples is on the right. If the concept of pages is new to you, just think of a page as a unit of space on the disk where multiple data instances are stored.
What does "only a fragment of the update cannot be placed into the database" mean?
This means that only a fragment of the update cannot be placed into the database, should a problem occur with either the hardware or the software involved. It is maintained in the presence of deadlocks. It is maintained in the presence of database software failures.
What does "class" mean in a table?
Class or table locking means that all instances of either a class or table are locked, as is illustrated below. This shows one form of concurrency control. Note the circle at the lower left. It represents all instances of a class, regardless of the page where they are stored.
What is data integrity?
Data integrity- The data integrity provides protection for the existence of the database and maintaining the quality of the database.
What is the first ACID property?
The first ACID property is atomicity. When an update occurs to a database, either all or none of the update becomes available to anyone beyond the user or application performing the update. This update to the database is called a transaction and it either commits or aborts.
Overview
What is a database?
- A database is a tool for collecting and organizing information. Databases can store information …
A computerized database is a container of objects. One database can contain more than one table. For example, an inventory tracking system that uses three tables is not three databases, but one database that contains three tables. Unless it has been specifically designed to use data or …
The parts of an Access database
- The following sections are short descriptions of the parts of a typical Access database.
Tables
- A database table is similar in appearance to a spreadsheet, in that data is stored in rows and col…
To get the most flexibility out of a database, the data needs to be organized into tables so that redundancies don't occur. For example, if you're storing information about employees, each employee should only need to be entered once in a table that is set up just to hold employee dat…
Forms
- Forms allow you to create a user interface in which you can enter and edit your data. Forms ofte…
You can program command buttons to determine which data appears on the form, open other forms or reports, or perform a variety of other tasks. For example, you might have a form named "Customer Form" in which you work with customer data. The customer form might have a butto…
Reports
- Reports are what you use to format, summarize and present data. A report usually answers a sp…
A report can be run at any time, and will always reflect the current data in the database. Reports are generally formatted to be printed out, but they can also be viewed on the screen, exported to another program, or sent as an attachment to an e-mail message.
Queries
- Queries can perform many different functions in a database. Their most common function is to r…
Certain queries are "updateable," meaning you can edit the data in the underlying tables via the query datasheet. If you are working in an updateable query, remember that your changes are actually being made in the tables, not just in the query datasheet. - Queries come in two basic varieties: select queries and action queries. A select query simply retr…
An action query, as the name implies, performs a task with the data. Action queries can be used to create new tables, add data to existing tables, update data, or delete data.
Macros
- Macros in Access can be thought of as a simplified programming language which you can use t…
For more information about macros, see the article Introduction to Access programming.
Modules
- Modules, like macros, are objects you can use to add functionality to your database. Whereas yo…
For more information about modules, see the article Introduction to Access programming.
Advantages of Using Database
- Database minimizes data redundancy to a great extent.
- The database can control the inconsistency of data to a largeextent.
- Sharing of data is also possible using the database.
- Database enforce standards.
Various Levels of Database Implementation
- The database is implemented through three general levels. Theselevels are: 1. Internal Level or Physical level 2. Conceptual Level 3. External Level or View Level
The Concept of Data Independence
- As the database may be viewed through three levels ofabstraction, any change at any level can affect other levels'schemas. Since the database keeps on growing, then there may befrequent changes at times. This should not lead to redesigning andre-implementation of the database. The concepts of dataindependence prove beneficial in such types of conte...