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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.

526 Questions

What are HEAP tables in MySQL?

Heap is no longer the accepted term for these kinds of tables in MySQL but it is still supported for backwards compatibility. The new accepted term is Memory and as the name suggest, Memory tables store their data directly in memory. Memory tables are used primarily as temporary tables. When you delete a row from a memory table, you do not free up space in the server memory. Space is only freed once the table is deleted.

How do you retrieve data stored in the database into the dropdown using PHP?

<select name="select1">

<option value="">Please Select...</option>

<?php

$fetchQuery = mysql_query("SELECT * FROM `table`");

while($showOutput = mysql_fetch_object($fetchQuery)){

echo "<option value="{$showOutput->value1}">{$showOutput->value2}</option>";

}

?>

</select>

Using the while function is very useful. If you wish to limit the amount of outputted lines, use LIMIT 10 at the end of the mysql query.

Lewis.

How do you create a schema in MySQL?

To create a schema (also known as a database), connect to your MySQL server with a program that allows you to send SQL commands. Common software usually includes phpMyAdmin or the MySQL Workbench utilities.

In the program, find a method of executing an SQL command to your server. You will then want to issue a CREATE statement, which will create a new schema. It can have a simple or complex syntax depending on your needs; see the related link for a full, official guide on this statement's syntax.

You what an E-R diagram of bank management?

An international bank has many head offices spread all across the world.Each head office control different branches located in country.Each country has many cities and each city has many branches.Each branches has three types of accounts - Savings,Current and Deposit for its customers.Identify the entities, attributes and relationship between them.

Where can information be found on how to do an MySQL update?

The MySQL UPDATE statement is one of the most commonly used commands in MySQL. The use is simple, but can be quite time consuming. Luckily there are professional tools like dbForge Studio for MySQL, that make all tasks faster and easier.

How many data types supported by MySQL?

Data types supported by MySQL are date and time data, numeric data, and byte data. Spatial data is another type supported by MySQL which includes the use of spatial extensions.

How do you select data associated with a logged in user from your sql davabase using php?

Assuming you have the same table for the user-details and login. Also that you have got the login part working

<?php

// connection string statement

// select database statement

// check if user is present in db

$user = 'user_name'; // put the value of username obtained from login

$select = mysql_query("SELECT * FROM table_name WHERE user='$user'");

// if statement will check for single user before showing data

if(($fetch = mysql_fetch_array($select))&&($select>0)&&($select<2))

{

// only print the columns you want to show

echo $fetch['col_1']; // where col_1 is the name of column

echo $fetch['col_2'];

}

?>

How do you find the MySQL version?

There are several ways to check your current version:

  • From the command line

  • Using Workbench

  • Via MySQL Client, exp. using dbForge Studio for MySQL

What is ER diagram for timetable management system?

An ER diagram is an "Entity Relationship" diagram, which illustrates the relationships between the entities in a data model.

A data model for a timetable management system might have entities like Days, Periods and Rooms. Its ER Diagram would then show that a Day is broken down into multiple Periods, and each Room might be used for multiple Periods.

What is the best open source PHP MySQL user management system?

There are many different user management systems available, many of which come bundled as part of other content management systems I'd suggest looking into something like Wordpress or Joomla to see how it can all work for you. Or check out a tutorial like http://www.roughguidetophp.com/creating-a-simple-comments-and-login-system-using-mysql-and-php/ to see how you can build something like that yourself

What is an LHS attribute?

oh dear,

I think you read it in a tutorial or something

LHS means the (Left Hand Side)

but there is noting specific called LHS attribute.

ex:

z = something

LHS here is (z)

What are the differences between MySQL and Foxpro?

Microsoft currently supports SQL Server and Visual FoxPro databases. Visual FoxPro, which Microsoft acquired and repurposed for use on Windows, had originally been designed for the DOS operating system, whereas SQL Server was built by Microsoft to be its High End Database.

SQL Server is a scalable database that can grow with your company. It's possible to add more users by updating the hardware to accommodate up to 4,600 users, as demonstrated by a recent benchmark test

It provides the highest level of security. By integrating network and server security, your data is safe from illegal access. User-level security means that users can restrict access to data records, making it difficult for others to alter or retrieve them. Furthermore, by storing the data on a separate server, the server serves as a firewall to prevent access by anyone who is not permitted.

For networks with an average of roughly 50 users, Visual FoxPro is an acceptable database. The DOS operating system introduced the File-Server application FoxPro. Individual PCs or local area networks were the intended target of this software. The data structure is easy to use, maintain, and secure. Larger networks can't use them because they lack the necessary security and scalability.

Network security is all or nothing. Users can add, alter, or delete information as soon as they have access to the data. However, a user's application software might include additional security measures that can be bypassed, giving them full control to make any changes they choose. In this case, the user's computer receives the data since it is stored on a local area network. The user's computer then processes the request. This results in delayed network response times and bottlenecks as multiple data blocks are sent over the network.

Visual FoxPro works well on small networks, but it can't handle a greater number of users. Several experts believe that Microsoft's support for this old system may be limited in the near future.

What is the basic form of a SQL statement to read data out of a table?

select * from Table

1.SELECT col1,col2,... from Tablename

2.SELECT col1,col2,...from Tablename WHERE condition

What is scalability?

Scalability is the aptitude of a system either hardware or software to maintain its functionality as it is changed in volume or size in order to meet a userÕs business needs. A system that scales appropriately is able to maintain or even improve its dependability and performance once experimented by greater working demand.

Can the stock trigger in a 270 caliber Ruger Model 77 Mark II be replaced with a two-stage trigger?

I'm not sure why you want a two stage trigger. There are a number of aftermarket triggers available from Timney, Jard, Rifle Basix and DAYTON TRAISTER for the Ruger M 77 MKII. Most require some fitting for the safety cam. Wolf Springs also offers replacement springs that will lighten the pull slightly. BS Firearms Services

Who developed MySQL?

MySQL was first developed by David Axmark, Allan Larsson and Michael "Monty" Widenius. It is an open source database software currently being managed by Oracle Corporation who bought Sun Microsystems, the previous "owners."

What are the example of external database?

what are the example of —external

what are the example of —external

Does Wordpress use MySQL?

Yes, WordPress uses one database which you set-up on installation. It's easy to set-up for those new to MySQL / PHP. It's simple and quick to set-up. WordPress is also a great Content Management Syste.

What is a Trigger in MySQL Define different types of Trigger?

A trigger is a named database object that is associated with a table, and that activates when a particular event occurs for the table. Some uses for triggers are to perform checks of values to be inserted into a table or to perform calculations on values involved in an update. A trigger is associated with a table and is defined to activate when an INSERT,DELETE, or UPDATE statement for the table executes. A trigger can be set to activate either before or after the triggering statement. For example, you can have a trigger activate before each row that is deleted from a table or after each row that is updated. Sender : Yugant khokhar

What does a Hierarchical database do?

A hierarchical model is a database model which represents the database in a tree diagram. It thus helps the user to work with(i.e., use, modify, extract etc.) the database without even bothering about the complicated algorithms or flow chart used by the system to deal with the database.

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.

Difference between mysql fetch row and mysql fetch array in PHP?

Both return a row in a MySQL database and in most applications can be used interchangeably. The difference is that mysql_fetch_array has an extra argument called $result_type that allows the returned array to be associative (string keys) or numeric (the keys are 0..n). A mysql_fetch_array call with the numeric parameter is equivalent to mysql_fetch_row.

How do different schema definition languages support the three schema architecture?

The three schema approach is used to build informational systems. The schema involves three different levels, which are the physical level, the conceptual level, and the external level.