MySQL

MySQL is a Relational Database Management System. It was first released in 1995 and is most commonly used with the PHP programming language. MySQL is open source and 100% free to use.

1,681 Questions
Database Programming
MySQL

What is data inconsistency?

Data inconsistency exists when different and conflicting versions of the

same data appear in different places. Data inconsistency creates

unreliable information, because it will be difficult to determine which

version of the information is correct. (It's difficult to make correct - and

timely - decisions if those decisions are based on conflicting information.)

Data inconsistency is likely to occur when there is data redundancy. Data

redundancy occurs when the data file/database file contains redundant -

unnecessarily duplicated - data. That's why one major goal of good

database design is to eliminate data redundancy.

434445
Major League Baseball (MLB)
Dwarf Planet Pluto
MySQL
Twilight New Moon

Are there any MLB stadiums named after a person?

Turner Field (Atlanta Braves), Wrigley Field (Chicago Cubs), Jacobs Field (Cleveland Indians), Busch Stadium (St. Louis Cardinals), and Kauffmann Stadium (Kansas City Royals) are all named after owners of the team. Shea Stadium (New York Mets) is named after the man credited with bringing National League Baseball back to New York. The Twins' home ballpark's full name isthe Hubert H. Humphrey Metrodome. The Washington Nationals used to play in RFK Stadiumwhich is named after Robert F. Kennedy.

616263
MySQL

How are locking techniques used for concurrency control?

Concurrency means use of database by many users at the same time.Concurrency control techniques (Different techniques) are used control multiple transactions interfere each other to produce wrong results.

therefore one of the main techniques used to control concurrent execution of transaction is based on the concept of locking of data item.

A lock is a variable associated with a data item in the database and describes the status of that item with respect to possible operation that can be applied to that item.

Generally there is a one lock for each data item in the database.

535455
Database Programming
Microsoft Access
MySQL

What is a database query?

A database query is a piece of code (a query) that is sent to a database in order to get information back from the database. It is used as the way of retriving the information from database

A database "query" is basically a "question" that you ask the database. The results of the query is the information that is returned by the database management system. Queries are usually constructed using SQL (structured query language) which resembles a high-level programming language.

The term 'query' means to search, to question, or to find. When you query a database, your searching for information in the database. Different query languages exist for different type of databases. MS Access uses SQL, which stands for Structured Query Language. MS Access contains Tables, Forms, and Queries. The Forms are used to enter or display the data, the Tables are where the data is saved, and the queries are used to search for specific data.

An example of an query can be this:

SELECT DISTINCT Agent FROM QAMonitoring ORDER BY Agent;

The query searches the 'Agent' field from the QAMonitoring table and sorts the list by last name. There are plenty of MS Access DB forums on the net for more info and help.

Creating a Simple Query in Microsoft Access

Have you ever wanted to combine information from multiple tables in your database in an efficient manner? Microsoft Access offers a powerful query function with an easy-to-learn interface that makes it a snap to extract exactly the information you need from your database. In this tutorial we'll explore the creation of a simple query.

In this example, as with all of our Access tutorials, we will use Access 2000 and the Northwind sample database included on the installation CD-ROM. If you're using an earlier version of Access, you may find that some of the menu choices and wizard screens are slightly different. However, the same basic principles apply to all versions of Access (as well as most database systems).

Let's explore the process step-by-step. Our goal in this tutorial is to create a query listing the names of all of our company's products, current inventory levels and the name and phone number of each product's supplier.

1. Open your database. If you haven't already installed the Northwind sample database, these instructions will assist you. Otherwise, go to the File tab, select Open and locate the Northwind database on your computer.

2. Select the queries tab. This will bring up a listing of the existing queries that Microsoft included in the sample database along with two options to create new queries.

3. Double-click on "create query by using wizard". The query wizard simplifies the creation of new queries. We'll use it in this tutorial to introduce the concept of query creation. In later tutorials we'll examine the Design view which facilitates the creation of more sophisticated queries.

353637
Software and Applications (non-game)
Database Programming
Visual Basic Programming
MySQL

Data flow diagram for inventory management system?

DFD for cold storage management system

272829
Computer Programming
Database Programming
PHP Programming
MySQL

Er diagram for online railway reservation system?

Er diagram

434445
Computer Terminology
Database Programming
MySQL

How do you draw entity relatoin in databases?

If the question is for databases, then the answer is in the link. If you want to store the ERDs in a database, then the question needs to be clarified to which database.

596061
PHP Programming
MySQL

How do you connect to mysql using vb6?

  1. Install the MyODBC database connector.
  2. Set up an new ODBC connection to your mysql database in Windows. (This will vary based on your version of Windows)
  3. You can use the ADODB extension in VB to connect to your ODBC connection.
535455
Database Programming
MySQL

What is the difference between mysql connect and mysql pconnect in PHP?

The difference between connect() and pconnect, it is simply like a shop when u entering in shop you will open the door and take your iteam come out and close the door that is called connect() in mysql the connection to the mysql database will be automatically closed when the script terminates.

when the door of the shop is already opend and never close it is called pconnect(), open a connection with mysql_pconnect(), the connection will not be closed and will "persist" for future use.

495051
MySQL

What is non-loss decomposition in database?

Nonloss-decomposition is data normalization without the loss of information.

555657
Swift Codes and Routing Numbers
The Difference Between
MySQL

What are nested transactions in MySQL?

Nested Transactions are transactions within transactions and are currently not supported by MySQL. Nested Transactions are not even vaguely related to Co-related Queries.

555657
Computer Programming
Database Programming
Database Design
MySQL

What are the disadvantages of relational databases?

There are no as such disadvantage of Relational database model . Relational DBMS define relationship between tables and also there is increased security. There can be a over head due to complexity in relations between tables and thus reduces throughput.

353637
Software and Applications (non-game)
Database Programming
MySQL

Can you join a table to itself?

Yes. In MySQL you can join a table to itself. You must use different alias name for each instance.

535455
C Programming
MySQL
ASP.NET

Data flow diagram for bus reservation system project?

please give me a Data Flow Diagram for railway Resarvation system

232425
Database Programming
Business Travel
MySQL

What are the disadvantages of a database?

An electronic database can contain so much data that maintaining file integrity can become a problem ultimately causing data degradation. Manual databases become harder to accurately search when they become large.

535455
Database Programming
MySQL
Oracle Database

What is the classification of DBMS and its interfaces?

Answer

DBMS Interfaces

User-friendly interfaces provided by a DBMS may include the following. � Menu-Based interfaces for Web Clients or Browsing: These interfaces present user with lists of options, called menus, that lead the user through the formulation a request. Menus do away with the need to memorize the specific commands and syntax of a query language. Pull-down menus are a very popular technique in Web based user interfaces. They are also often used in browsing interfaces, which allows a user to look through the contents of a database. � Forms-Based Interfaces: A forms-based interface displays a form to each user. Forms are usually designed and programmed for naive users as interfaces to canned transactions. Some systems have utilities that define a form by letting the end user interactively construct a sample form on the screen. � Graphical User Interfaces: A graphical interface (GUI) typically displays a schema to the user in diagrammatic form. The user can then specify a query by manipulating diagram. In many cases, GUls utilize both menus and forms. Most GUls use a pointing device, such as a mouse, to pick certain parts of the displayed schema diagram. � Natural Language Interfaces: These interfaces accept requests written in English, Hindi or some other language and attempt to "understand" them. A natural language interface usually has its own "schema," which is similar to the database conceptual schema, as well as a dictionary of important words. � Interfaces for Parametric Users: Parametric users, such as bank tellers, often have a small set of operations that they must perform repeatedly. Systems analysts and programmers design and implement a special interface for each known class of na�ve users. Usually, a small set of abbreviated commands is included, with the goal of minimizing the number of keystrokes required for each request. For example, function keys in a terminal can be programmed to initiate the various commands. � Interfaces for the DBA. Most database systems contain privileged commands that can be used only by the DBA's staff. These include commands for creating account, setting system parameters, granting account authorization, changing a schema, and reorganizing the storage structures of a database.

505152
Internet
PHP Programming
MySQL
Oracle Database

E-R diagram for help desk management?

HOLA

525354
C Programming
The Difference Between
MySQL

Difference between printf and fprintf?

printf (*) is equal to fprintf (stdout, *)

515253
Computer Programming
Database Programming
MySQL
Oracle Database

Classification of DBMS?

I.Data Model

a. Traditional: Relational, Network, Hierarchical

b. Emerging: Object-oriented, Object-relational

II.Number of Users

a. Single-user (typically used with micro-computers)vs. multi-user (most DBMSs)

b. Centralized (uses a single computer with onen database)vs. distributed (uses multiple computers, multiple databases)

III.Number of Sites

IV.Cost

V.Types of Access Path

VI.Purpose

505152
MySQL

What does MySQL error number 10060 mean?

There is, in fact, no MySQL error with that number. The actual error number is at the beginning of the message (i.e.: ERROR 2003: Can't connect to MySQL server (10060)"). Typically though, when you see that number it is related to an authentication issue of some sort. Either you are trying to authenticate (log in) from an IP address/host that isn't authorized to or there is a problem related to the MySQL server's TCP/IP bindings. There are four common reasons why you would get an error message like this: 1) The MySQL server isn't running. 2) MySQL's configuration file specifies that it is only listening on a certain IP:Port and that you're not communicating through the specified address (i.e.: Your MySQL server's system has multiple NICs and you are communicating with the server through the NIC not specified). 3) You have the MySQL server is being started with the --skip-networking option enabled either from the startup script or in the .conf file. 4) The user name being used to authenticate to the MySQL server is not allowed to connect from the client computer's IP address/host (i.e.: User "Alice" is only allowed to log in from 192.168.0.100 but is trying to log in from 192.168.0.200). Link: http://dev.mysql.com/doc/refman/5.1/en/can-not-connect-to-server.html

515253
Chicago Cubs
Database Design
MySQL

What does it mean to qualify a field name?

A field is the name given to the column or attribute. A field name cannot be empty and also it cannot be an identifier. Example in a table stud there are fields like Fname, Lname, Rollno etc

91011
Computer Programming
Job Applications
HTML
MySQL

What is demonstrated high level of initiative?

It means that the person is a self-starter; she or he can start projects independently, or perhaps actively looks for solutions beyond the minimum required. The person can probably motivate others to come on board with a project. When you "initiate" something, you start it. That is the general sense of the word "initiative".

414243
Computers
Database Programming
MySQL
Oracle Database

What is an ER Diagram?

Entity Relationship Diagram is a high-level description of a conceptual data model.

495051
PHP Programming
MySQL

How do you call stored procedures in PHP using MYSQL?

Considering you have colavg() SP defined in Mysql on table 'city' which calculate the average of population.

Example:

PHP Code:

include 'connect_db.php';

$dbclass=new db_connector();

$dbh=$dbclass->getDBH();

$res=mysql_query("CALL colavg('city','population')",$dbh);

while($data = mysql_fetch_array($res))

{

print_r($data);

}

connect_db.php

Returns the mysql database handler resource.

474849
Database Programming
Database Design
MySQL

How can I design a good database?

A good database is nothing but something non-redundant and integrated. To design a good database one must know what is his/her requirements what tables they want , fields (attributes), relationship between them. Keeping all the requirements in mind one can design a good database design.

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