PHP uses pdo to connect to the access database and loop through the data manipulation sample
- 2021-10-15 10:04:17
- OfStack
This article illustrates how PHP uses pdo to connect to an access database and display data operations in a loop. Share it for your reference, as follows:
PDO Connection and Query:
try {
$conn = new PDO("odbc:driver={microsoft access driver (*.mdb)};
dbq=".realpath("MyDatabase.mdb"))
or die(" Link error! ");
//echo " Link successful! ";
}
catch(PDOException $e){
echo $e->getMessage();
}
$sql = "select * from users";
1.
foreach()
Method
foreach ($conn->query($sql) as $row) {
$row["UserID"];
$row["UserName"];
$row["UserPassword"];
}
2.
while()
Method
$rs = $conn->query($sql);
$rs->setFetchMode(PDO::FETCH_NUM);
while($row=$rs->fetch()){
$row[0];
$row[1];
$row[2];
}
php uses PDO abstraction layer to obtain query results in three main ways:
(1)
PDO::query()
Query.
Look at the following php code:
<?php
//PDO::query() Query
$res = $db->query('select * from user');
$res->setFetchMode(PDO::FETCH_NUM); // Digital indexing mode
while ($row = $res->fetch()){
print_r($row);
}
?>
(2)
PDO->exec()
Processing sql
<?php
//PDO->exec() Deal with sql
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
$res = $db->exec("insert into user(id,name) values('','php Point-to-point communication ')");
echo $res;
?>
(3)
PDO::prepare()
Preprocessing executes queries
<?php
//PDO::prepare() Preprocessing executes queries
$res = $db->prepare("select * from user");
$res->execute();
while ($row = $res->fetchAll()) {
print_r($row);
}
?>
setAttribute()
The method is to set the properties, and the common parameters are as follows:
PDO:: CASE_LOWER--Force column names to be lowercase
PDO:: CASE_NATURAL--Column name as original
PDO:: CASE_UPPER--Force column names to uppercase
setFetchMode
Method to set the type of return value to get the result set. The common parameters are as follows:
PDO:: FETCH_ASSOC--associative array form
PDO:: FETCH_NUM--Digital index array form
PDO:: FETCH_BOTH--Both in array form, which is the default
PDO:: FETCH_OBJ--In the form of an object, similar to the previous mysql_fetch_object ()
The above is summarized as follows:
Query operations are mainly
PDO::query()
,
PDO::exec()
,
PDO::prepare()
.
PDO-
>
query ()--Processes 1 SQL statement and returns 1 "PDOStatement"
PDO-
>
exec ()--Processes 1 SQL statement and returns the number of entries affected
PDO::prepare()
It is mainly preprocessing operation, which needs to pass $rs-
>
execute () to execute the SQL statement in the preprocessing
Finally, two commonly used functions are introduced:
(1)
fetchColumn()
Get the result of 1 field in the specified record, and the default is the first field!
<?php
$res = $db->query('select * from user');
// Gets the number in the specified record 2 Field results
$col = $res->fetchColumn(1);
echo $col;
?>
(2)
fetchAll()
Obtain data from a result set and store it in an associative array
<?php
$res = $db->query('select * from user');
$res_arr =$res->fetchAll();
print_r($res_arr);
?>
For more readers interested in PHP related content, please check the topics on this site: "Summary of PHP Database Operation Skills Based on pdo", "Summary of php+Oracle Database Programming Skills", "Encyclopedia of PHP+MongoDB Database Operation Skills", "Introduction to php Object-Oriented Programming", "Summary of php String (string) Usage", "Introduction to php+mysql Database Operation Skills" and "Summary of php Common Database Operation Skills"
I hope this article is helpful to everyone's PHP programming.