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如何用Perl访问SQLite数据库
SQLite是一个零配置，无服务端，基于文件的事务文件系统。由于它的轻量级，自包含和紧凑的设计，所以当你想要集成数据库到你的程序中时，SQLite是一个非常流行的选择。在这篇文章中，我会展示如何用Perl脚本来创建和访问SQLite数据库。我演示的Perl代码片段是完整的，所以你可以很简单地修改并集成到你的项目中。
访问SQLite的准备
我会使用SQLite DBI Perl驱动来连接到SQLite3。因此你需要在Linux中安装它（和SQLite3一起）。
Debian、 Ubuntu 或者 Linux Mint
$ sudo apt-get install sqlite3 libdbd-sqlite3-perl
CentOS、 Fedora 或者 RHEL
$ sudo yum install sqlite perl-DBD-SQLite
安装后，你可以检查SQLite驱动可以通过下面的脚本访问到。
#!/usr/bin/perl
my @drv = DBI->available_drivers();
print join("\n", @drv), "\n";
如果你运行脚本，你应该会看见下面的输出。
DBM
ExampleP
File
Gofer
Proxy
SQLite
Sponge
Perl SQLite 访问示例
下面就是Perl访问SQLite的示例。这个Perl脚本会演示下面这些SQLite数据库的常规管理。
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创建和连接SQLite数据库
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在SQLite数据库中创建新表
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在表中插入行
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在表中搜索和迭代行
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在表中更新行
-
在表中删除行
use DBI; use strict;
define database name and driver
my $driver = "SQLite"; my $db_name = "xmodulo.db"; my $dbd = "DBI:$driver:dbname=$db_name";
sqlite does not have a notion of username/password
my $username = ""; my $password = "";
create and connect to a database.
this will create a file named xmodulo.db
my $dbh = DBI->connect($dbd, $username, $password, { RaiseError => 1 }) or die $DBI::errstr; print STDERR "Database opened successfully\n";
create a table
my $stmt = qq(CREATE TABLE IF NOT EXISTS NETWORK (ID INTEGER PRIMARY KEY AUTOINCREMENT, HOSTNAME TEXT NOT NULL, IPADDRESS INT NOT NULL, OS CHAR(50), CPULOAD REAL);); my $ret = $dbh->do($stmt); if($ret < 0) { print STDERR $DBI::errstr; } else { print STDERR "Table created successfully\n"; }
insert three rows into the table
$stmt = qq(INSERT INTO NETWORK (HOSTNAME,IPADDRESS,OS,CPULOAD) VALUES ('xmodulo', 16843009, 'Ubuntu 14.10', 0.0)); $ret = $dbh->do($stmt) or die $DBI::errstr;
$stmt = qq(INSERT INTO NETWORK (HOSTNAME,IPADDRESS,OS,CPULOAD) VALUES ('bert', 16843010, 'CentOS 7', 0.0)); $ret = $dbh->do($stmt) or die $DBI::errstr;
$stmt = qq(INSERT INTO NETWORK (HOSTNAME,IPADDRESS,OS,CPULOAD) VALUES ('puppy', 16843011, 'Ubuntu 14.10', 0.0)); $ret = $dbh->do($stmt) or die $DBI::errstr;
search and iterate row(s) in the table
$stmt = qq(SELECT id, hostname, os, cpuload from NETWORK;); my $obj = $dbh->prepare($stmt); $ret = $obj->execute() or die $DBI::errstr;
if($ret < 0) { print STDERR $DBI::errstr; } while(my @row = $obj->fetchrow_array()) { print "ID: ". $row[0] . "\n"; print "HOSTNAME: ". $row[1] ."\n"; print "OS: ". $row[2] ."\n"; print "CPULOAD: ". $row[3] ."\n\n"; }
update specific row(s) in the table
$stmt = qq(UPDATE NETWORK set CPULOAD = 50 where OS='Ubuntu 14.10';); $ret = $dbh->do($stmt) or die $DBI::errstr;
if( $ret < 0 ) { print STDERR $DBI::errstr; } else { print STDERR "A total of $ret rows updated\n"; }
delete specific row(s) from the table
$stmt = qq(DELETE from NETWORK where ID=2;); $ret = $dbh->do($stmt) or die $DBI::errstr;
if($ret < 0) { print STDERR $DBI::errstr; } else { print STDERR "A total of $ret rows deleted\n"; }
quit the database
$dbh->disconnect(); print STDERR "Exit the database\n";
上面的Perl脚本运行成功后会创建一个叫“xmodulo.db”的数据库文件，并会有下面的输出。
Database opened successfully
Table created successfully
ID: 1
HOSTNAME: xmodulo
OS: Ubuntu 14.10
CPULOAD: 0
ID: 2
HOSTNAME: bert
OS: CentOS 7
CPULOAD: 0
ID: 3
HOSTNAME: puppy
OS: Ubuntu 14.10
CPULOAD: 0
A total of 2 rows updated
A total of 1 rows deleted
Exit the database
错误定位
如果你尝试没有安装SQLite DBI驱动的情况下使用Perl访问SQLite的话，你会遇到下面的错误。你必须按开始说的安装DBI驱动。
Can't locate DBI.pm in @INC (@INC contains: /usr/local/lib64/perl5 /usr/local/share/perl5 /usr/lib64/perl5/vendor_perl /usr/share/perl5/vendor_perl /usr/lib64/perl5 /usr/share/perl5 .) at ./script.pl line 3.
BEGIN failed--compilation aborted at ./script.pl line 3.
via: http://xmodulo.com/access-sqlite-database-perl.html