Ingaba idatabase yeMySQL ibuza njani idatha kwitafile?iNgxelo yoMbuzo/Umyalelo/Isintaksi

MySQL databaseIndlela yokubuza idatha kwitheyibhile?iNgxelo yoMbuzo/uMyalelo/Isintaksi

MySQL Idatha yombuzo

Oovimba beenkcukacha ze-MySQL zisebenzisa i-SQL KHETHA iingxelo zokubuza iinkcukacha.

Unokubuza idatha kwisiseko sedatha nge-mysql> iwindow yomyalelo womyalelo, okanye ngeskripthi se-PHP.

Igrama

Oku kulandelayo yi-KHETHA isivakalisi sokubuza imibuzo kwisiseko sedatha seMySQL:

SELECT column_name,column_name
FROM table_name
[WHERE Clause]
[OFFSET M ][LIMIT N]

• Kwingxelo yombuzo, ungasebenzisa itheyibhile enye okanye ezininzi, zahlula iitafile ngeekoma (,), kwaye usebenzise i-WHERE isitatimenti ukuseta iimeko zombuzo.
• Umyalelo KHETHA unokufunda irekhodi enye okanye ngaphezulu.
• Ungasebenzisa i asterisk (*) ukubuyisela eminye imihlaba, ingxelo KHETHA izakubuyisela yonke idata yendawo yetafile.
• Ungasebenzisa i-WHERE ingxelo ukubandakanya nayiphi na imeko.
• Ungakhankanya i-offset yedatha apho i-SELECT statement iqala khona umbuzo nge-OFFSET.Ngokusisiseko i-offset ngu-0.
• Ungasebenzisa i-LIMIT impahla ukuseta inani leerekhodi ezibuyisiweyo.

Fumana idatha ngomyalelo womyalelo

Kulo mzekelo ulandelayo, siya kusebenzisa umyalelo we-SQL KHETHA ukufumana idatha yetafile yedatha ye-MySQL chenweiliang_tbl:

Umzekelo

Lo mzekelo ulandelayo uya kubuyisela zonke iirekhodi zedatha yetheyibhile chenweiliang_tbl:

select * from chenweiliang_tbl;

Sebenzisa iscript sePHP ukufumana idatha

usebenzisa imisebenzi ye-PHP mysqli_query() Kwaye SQL KHETHA umyalelo wokufumana idatha.

Lo msebenzi usetyenziselwa ukuphumeza imiyalelo ye-SQL kwaye ugqithise imisebenzi ye-PHP mysqli_fetch_array() ukusebenzisa okanye ukukhupha idatha kuyo yonke imibuzo.

mysqli_fetch_array() Umsebenzi ulanda umqolo kwisiphumo esisetiyo njengoluhlu lonxulumano, okanye uluhlu lwamanani, okanye zombini.Ibuyisela uluhlu oluveliswe kwimiqolo ethatyathwe kwiseti yesiphumo, okanye bubuxoki ukuba akusekho migca.

Lo mzekelo ulandelayo ufunda zonke iirekhodi kwitheyibhile yedatha chenweiliang_tbl.

Umzekelo

Zama lo mzekelo ulandelayo ukubonisa zonke iirekhodi zetafile yedatha chenweiliang_tbl.

<?
php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
 die('连接失败: ' . mysqli_error($conn));
}
// 设置编码，防止中文乱码
mysqli_query($conn , "set names utf8");
 
$sql = 'SELECT chenweiliang_id, chenweiliang_title, 
 chenweiliang_author, submission_date
 FROM chenweiliang_tbl';
 
mysqli_select_db( $conn, 'chenweiliang' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
 die('无法读取数据: ' . mysqli_error($conn));
}
echo '<h2>陈沩亮博客 mysqli_fetch_array 测试<h2>';
echo '<table border="1"><tr><td>教程 ID</td><td>标题</td><td>作者</td><td>提交日期</td></tr>';
while($row = mysqli_fetch_array($retval, MYSQL_ASSOC))
{
 echo "<tr><td> {$row['chenweiliang_id']}</td> ".
 "<td>{$row['chenweiliang_title']} </td> ".
 "<td>{$row['chenweiliang_author']} </td> ".
 "<td>{$row['submission_date']} </td> ".
 "</tr>";
}
echo '</table>';
mysqli_close($conn);
?>

Kulo mzekelo ungentla, umqolo ngamnye weerekhodi ezifundiweyo unikezelwe kwi-variable $row, kwaye ke ixabiso ngalinye liprintwe.

Qaphela:Khumbula ukuba ukuba ufuna ukusebenzisa i-variable kumtya, faka ukuguquguquka kwiibrayisi ezigobileyo.

Kulo mzekelo ungasentla, iparameter yesibini ye PHP mysqli_fetch_array() umsebenzi ngu MYSQL_ASSOC, cwangcisa le parameter ukubuza isiphumo ukubuyisela uluhlu lonxulumano, ungasebenzisa igama lomhlaba njengesalathiso soluhlu.

PHP inika omnye umsebenzi mysqli_fetch_assoc(), umsebenzi uthatha umqolo kwisiphumo esisetiweyo njengoluhlu lonxulumano.Ibuyisela uluhlu oluhlangeneyo oluveliswe kwimiqolo ethatyathwe kwiseti yesiphumo, okanye bubuxoki ukuba akusekho mqolo.

Umzekelo

Zama lo mzekelo ulandelayo, osebenzisa mysqli_fetch_assoc() umsebenzi wokukhupha zonke iirekhodi zetafile yedatha chenweiliang_tbl:

<?
php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
 die('连接失败: ' . mysqli_error($conn));
}
// 设置编码，防止中文乱码
mysqli_query($conn , "set names utf8");
 
$sql = 'SELECT chenweiliang_id, chenweiliang_title, 
 chenweiliang_author, submission_date
 FROM chenweiliang_tbl';
 
mysqli_select_db( $conn, 'chenweiliang' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
 die('无法读取数据: ' . mysqli_error($conn));
}
echo '<h2>陈沩亮博客 mysqli_fetch_assoc 测试<h2>';
echo '<table border="1"><tr><td>教程 ID</td><td>标题</td><td>作者</td><td>提交日期</td></tr>';
while($row = mysqli_fetch_assoc($retval))
{
 echo "<tr><td> {$row['chenweiliang_id']}</td> ".
 "<td>{$row['chenweiliang_title']} </td> ".
 "<td>{$row['chenweiliang_author']} </td> ".
 "<td>{$row['submission_date']} </td> ".
 "</tr>";
}
echo '</table>';
mysqli_close($conn);
?>

Ungasebenzisa i-MYSQL_NUM engaguqukiyo njenge parameter yesibini ye PHP mysqli_fetch_array() umsebenzi, obuyisela uluhlu lwamanani.

Umzekelo

Le mizekelo ilandelayo iyasetyenziswa MYSQL_NUM Ipharamitha ibonisa zonke iirekhodi zetafile yedatha chenweiliang_tbl:

<?
php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
 die('连接失败: ' . mysqli_error($conn));
}
// 设置编码，防止中文乱码
mysqli_query($conn , "set names utf8");
 
$sql = 'SELECT chenweiliang_id, chenweiliang_title, 
 chenweiliang_author, submission_date
 FROM chenweiliang_tbl';
 
mysqli_select_db( $conn, 'chenweiliang' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
 die('无法读取数据: ' . mysqli_error($conn));
}
echo '<h2>陈沩亮博客 mysqli_fetch_array 测试<h2>';
echo '<table border="1"><tr><td>教程 ID</td><td>标题</td><td>作者</td><td>提交日期</td></tr>';
while($row = mysqli_fetch_array($retval, MYSQL_NUM))
{
 echo "<tr><td> {$row[0]}</td> ".
 "<td>{$row[1]} </td> ".
 "<td>{$row[2]} </td> ".
 "<td>{$row[3]} </td> ".
 "</tr>";
}
echo '</table>';
mysqli_close($conn);
?>

ukukhululwa kwenkumbulo

Luqheliselo olulungileyo ukukhulula inkumbulo yekhesa emva kokuba senze ingxelo KHETHA.

Imemori inokukhutshwa ngomsebenzi we-PHP mysqli_free_result ().

Lo mzekelo ulandelayo ubonisa ukusetyenziswa kwalo msebenzi.

Umzekelo

Zama le mizekelo ilandelayo:

Inkumbulo yasimahla enesiphumo se-mysqli_free:

<?
php
$dbhost = 'localhost:3306'; // mysql服务器主机地址
$dbuser = 'root'; // mysql用户名
$dbpass = '123456'; // mysql用户名密码
$conn = mysqli_connect($dbhost, $dbuser, $dbpass);
if(! $conn )
{
 die('连接失败: ' . mysqli_error($conn));
}
// 设置编码，防止中文乱码
mysqli_query($conn , "set names utf8");
 
$sql = 'SELECT chenweiliang_id, chenweiliang_title, 
 chenweiliang_author, submission_date
 FROM chenweiliang_tbl';
 
mysqli_select_db( $conn, 'chenweiliang' );
$retval = mysqli_query( $conn, $sql );
if(! $retval )
{
 die('无法读取数据: ' . mysqli_error($conn));
}
echo '<h2>陈沩亮博客 mysqli_fetch_array 测试<h2>';
echo '<table border="1"><tr><td>教程 ID</td><td>标题</td><td>作者</td><td>提交日期</td></tr>';
while($row = mysqli_fetch_array($retval, MYSQL_NUM))
{
 echo "<tr><td> {$row[0]}</td> ".
 "<td>{$row[1]} </td> ".
 "<td>{$row[2]} </td> ".
 "<td>{$row[3]} </td> ".
 "</tr>";
}
echo '</table>';
// 释放内存
mysqli_free_result($retval);
mysqli_close($conn);
?>