PHP mysqli: select_db() function
mysqli_select_db() function/ mysqli::select_db
The mysqli_select_db() function/ mysqli::select_db is used to change the default database for the connection.
Syntax:
Object oriented style
bool mysqli::select_db ( string $dbname )
Procedural style
bool mysqli_select_db ( mysqli $link , string $dbname )
Parameter:
Name | Description | Required/Optional | |
---|---|---|---|
link | A link identifier returned by mysqli_connect() or mysqli_init() | Required for procedural style only and Optional for Object oriented style | |
dbname | The database name. | Required |
Usage: Procedural style
mysqli_select_db(connection,dbname);
Parameter:
Name | Description | Required/Optional |
---|---|---|
connection | Specifies the MySQL connection to use | Required |
dbname | Specifies the default database to be used | Required |
Return value:
Returns TRUE on success or FALSE on failure.
Version: PHP 5, PHP 7
Example of object oriented style:
<?php
$mysqli = new mysqli("localhost", "user1", "datasoft123", "hr");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* return name of current default database */
if ($result = $mysqli->query("SELECT DATABASE()")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
/* change db to world db */
$mysqli->select_db("hr");
/* return name of current default database */
if ($result = $mysqli->query("SELECT DATABASE()")) {
$row = $result->fetch_row();
printf("Default database is %s.\n", $row[0]);
$result->close();
}
$mysqli->close();
?>
Output:
Default database is hr. Default database is hr.
Example of the Procedural style
<?php
$link = mysqli_connect("localhost", "user1", "datasoft123", "hr");
/* check connection */
if (mysqli_connect_errno()) {
printf("Connect failed: %s\n", mysqli_connect_error());
exit();
}
/* return name of current default database */
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
printf("Default database is %s.\n", $row[0]);
mysqli_free_result($result);
}
/* change db to world db */
mysqli_select_db($link, "hr");
/* return name of current default database */
if ($result = mysqli_query($link, "SELECT DATABASE()")) {
$row = mysqli_fetch_row($result);
printf("Default database is %s.\n", $row[0]);
mysqli_free_result($result);
}
mysqli_close($link);
?>
Output:
Default database is hr. Default database is hr.
See also
Previous: rollback
Next: set_charset
PHP: Tips of the Day
To use the constant simply use its name:
Example:
if (EARTH_IS_FLAT) { print "Earth is flat"; } print APP_ENV_UPPERCASE;
Output:
or if you don't know the name of the constant in advance, use the constant function:
// this code is equivalent to the above code $const1 = "EARTH_IS_FLAT"; $const2 = "APP_ENV_UPPERCASE"; if (constant($const1)) { print "Earth is flat"; } print constant($const2);
Output:
- Weekly Trends
- Java Basic Programming Exercises
- SQL Subqueries
- Adventureworks Database Exercises
- C# Sharp Basic Exercises
- SQL COUNT() with distinct
- JavaScript String Exercises
- JavaScript HTML Form Validation
- Java Collection Exercises
- SQL COUNT() function
- SQL Inner Join
- JavaScript functions Exercises
- Python Tutorial
- Python Array Exercises
- SQL Cross Join
- C# Sharp Array Exercises
We are closing our Disqus commenting system for some maintenanace issues. You may write to us at reach[at]yahoo[dot]com or visit us at Facebook