MySQL Function Reference
This section lists PHP functions for interacting with a MySQL server. We've divided them into those that are frequently used and those that are less frequently used. We've also included a list of the functions we don't use, and the reasons why you should avoid them. We recommend that at a minimum you read the information about the five main functions we've used in this chapter: mysql_connect( ), mysql_select_db( ), mysql_query( ), mysql_fetch_array( ), and mysql_error( ).
Web database applications can be developed with only a few functions. However, in many cases, additional functionality is required. For example, you may want to choose performance-conscious alternatives and it's often useful to retrieve only a part of the data without processing the complete dataset. Functions for all of these tasks are described in this section. Writing data to a database and the functions mysql_affected_rows( ) and mysql_insert_id( ) are discussed in more detail in Chapter 8.
Frequently Used Functions
- int mysql_affected_rows([resource
connection]) Returns the number of rows affected by the last
UPDATE,DELETE, orINSERTSQL statement, and -1 if the last query failed. The function takes as an optional parameter a server connection resource handle. If no parameter is passed, the most recently opened connection is assumed.This function doesn't work for
SELECTstatements; mysql_num_rows( ) should be used instead.For example, if a customer is deleted with the SQL statement: ...
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