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Once we have already explained a little superficially all the possible and logical operations that we can do with a database in the language SQL, there comes the moment to combine it with the PHP potency and for it we will use the program MySQL.
MySQL is one of the agents of databases more used in environments in which PHP is used since PHP has numerous functions that are combined perfectly with MySQL. The generic way of obtaining stage information in Mysql is the following one:
- Connection with the agent.
- Preparation of the consultation SQL.
- Execution of the consultation.
- Prosecution of the result obtained in the cursor.
- Liberation of resources (this one is optional, although it is advisable).
- Closing of the connection with the agent.
To realize you are and many other more things we have the following functions:
| Function |
Description |
| mysql_connect ("host", "user", "password") |
It establishes the connection with the servant. There receives the host and the user and password with the one that must tune in. |
| mysql_select_db ("database", connection) |
It selects the database on which it goes to work |
| mysql_query (consultation, connection) |
He executes the consultation SQL indicated like the first parameter. |
| mysql_num_fields (cursor) |
He returns the number of attributes that appear in the cursor that passes to him like parameter and in the one that stores the result of the consultation |
| mysql_fetch_row (cursor) |
It advances to the following position of the line in cursor. He returns an array that each of the values contains in his cells of the attributes of the line. |
| mysql_free_result (cursor) |
It liberates the resources associated with the cursor. |
| mysql_close (connection) |
It closes the connection established with mysql_connect. |
One of the advantages that provides the highest integration that PHP and MYSQL have is the existence of functions that allow to the programmer to gain access to the different structures that agree the database. Some of the functions are:
| Function |
Description |
| mysql_list_dbs (connection) |
He returns in a cursor the names of the available databases in the servant to whom it has got connected with mysql_connect |
| mysql_list_tables (base_datos, connection) |
He returns in a cursor the names of the available stage in the database. |
| mysql_tablename (cursor, numero_fila) |
He returns the name of the table or database in which the stated cursor is |
| mysql_field_name (cursor, numero_col) |
He returns the name of the field which index passes like the second parameter |
| mysql_field_type (cursor, numero_Col) |
He returns the type of the field which index passes like the second parameter |
| mysql_field_len (cursor, numero_col) |
He returns the length of the field which index passes like the second parameter |
| mysql_field_flags (cursor, numero_col) |
He returns a series of indicative corresponding to characteristics of the attribute which index passes like the second parameter |
| mysql_affected_rows (connection) |
He returns the number of lines affected by an update or erasure |
| mysql_change_user (user, password) |
It changes user |
| mysql_create_db (basedatos) |
Believe a database with the name spent by parameter |
| mysql_drop_db (basedatos) |
It eliminates the database spent by parameter |
| mysql_insert_id (cursor) |
He returns the value generated for an AUTOINCREMENT |
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Connection with MySQL 
