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The following example of a SELECT query returns a list of expensive books. The query retrieves all rows from the Book table in which the price column contains a value greater than 100.00. The result is sorted in ascending order by title. The asterisk (*) in the select list indicates that all columns of the Book table should be included in the ...
The following example of a SELECT query returns a list of expensive books. The query retrieves all rows from the Book table in which the price column contains a value greater than 100.00. The result is sorted in ascending order by title. The asterisk (*) in the select list indicates that all columns of the Book table should be included in the ...
PHP treats newlines as whitespace in the manner of a free-form language, and statements are terminated by a semicolon. [218] PHP has three types of comment syntax: /* */ marks block and inline comments; // or # are used for one-line comments. [219] The echo statement is one of several facilities PHP provides to output text. [citation needed]
Query by Example (QBE) is a database query language for relational databases. It was devised by Moshé M. Zloof at IBM Research during the mid-1970s, in parallel to the development of SQL . [ 1 ] It is the first graphical query language, using visual tables where the user would enter commands, example elements and conditions.
To use PHP with an HTML form, the URL of the PHP script is specified in the action attribute of the form tag. The target PHP file then accesses the data passed by the form through PHP's $_POST or $_GET variables, depending on the value of the method attribute used in the form. Here is a basic form handler PHP script that will display the ...
Use a form to capture user input, and then process, verify and respond to that data without having to send data back to the server. Include rollover buttons or drop-down menus. A less common use is to create browser-based action games.
Functions could be used in SELECT statements, provided they do no data manipulation. However, procedures cannot be included in SELECT statements. A stored procedure can return multiple values using the OUT parameter, or return no value. A stored procedure saves the query compiling time. A stored procedure is a database object.
A connection is required to send commands and receive answers, usually in the form of a result set. Connections are a key concept in data-centric programming. Since some DBMS engines require considerable time to connect, connection pooling was invented to improve performance. No command can be performed against a database without an "open and ...