Indlela yokujonga isimo kunye nenombolo yedatha yedatha yesakhiwo solwazi lwedatha yedatha ye-MySQL?

MySQL metadata

Unokufuna ukwazi ezi ntlobo zintathu zilandelayo zolwazi malunga ne-MySQL:

• Ulwazi lweziphumo zombuzo: Inani leerekhodi ezichatshazelwa yi-KHETHA, UKUHLAZIYA okanye UKUCIMA ingxelo.
• Ulwazi malunga nogcino-lwazi kunye neetafile zedatha: Iqulethe ulwazi lwesakhiwo sesiseko sedatha kunye nedatha yedatha.
• Ulwazi lweseva ye-MySQL: Iqulethe imo yangoku yeseva yedatha, inombolo yoguqulelo, njl.

Kwi-MySQL command prompt, sinokufumana lula ulwazi lweseva engentla.Kodwa ukuba usebenzisa ulwimi lokubhala olunje ngePerl okanye i-PHP, kufuneka ufowunele umsebenzi othile wojongano ukuze uwufumane.Okulandelayo siza kwazisa ngokweenkcukacha.

Fumana inani leerekhodi ezichatshazelwa yingxelo yombuzo

Umzekelo wePERL

Kwimibhalo ye-DBI, inani leerekhodi ezichatshazelwe yingxelo libuyiswa yimisebenzi do( ) okanye phunyezwa ( ):

# 方法 1
# 使用do( ) 执行  $query 
my $count = $dbh->do ($query);
# 如果发生错误会输出 0
printf "%d 条数据被影响\n", (defined ($count) ? $count : 0);
# 方法 2
# 使用prepare( ) 及 execute( ) 执行  $query 
my $sth = $dbh->prepare ($query);
my $count = $sth->execute ( );
printf "%d 条数据被影响\n", (defined ($count) ? $count : 0);

Umzekelo we-PHP

Kwi PHP, ungasebenzisa mysqli_affected_rows () umsebenzi ukufumana inani leerekhodi ezichatshazelwe ngumbuzo.

$result_id = mysqli_query ($conn_id, $query);
# 如果查询失败返回 
$count = ($result_id ? mysqli_affected_rows ($conn_id) : 0);
print ("$count 条数据被影响\n");

Uluhlu lweedathabheyisi kunye neetafile zedatha

Unokufumana ngokulula uluhlu lweenkcukacha kunye neetafile kwiseva ye-MySQL.Ukuba ngaba awunazo iimvume ezaneleyo, isiphumo siya kubuya ungekho.
Ungasebenzisa kwakhona i-SHOW TABILES okanye BONISA IIDATHASESTI ukuze ufumane uluhlu lwedatabase kunye neetafile zedatha.

Umzekelo wePERL

# 获取当前数据库中所有可用的表。
my @tables = $dbh->tables ( );
foreach $table (@tables ){
   print "表名 $table\n";
}

Umzekelo we-PHP

Lo mzekelo ulandelayo uvelisa zonke iinkcukacha kwiseva yeMySQL:

<?
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
$db_list = mysqli_query($conn, 'SHOW DATABASES');
while ($db = mysqli_fetch_object($db_list))
{
 echo $db->Database . "<br />";
}
mysqli_close($conn);
?>

Fumana imetadata yeseva

Ezi ngxelo zilandelayo zomyalelo zingasetyenziswa kwi-MySQL yomyalelo wokukhawuleza okanye kwizikripthi, ezifana nezikripthi ze-PHP.