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174 lines
5.5 KiB
Markdown
174 lines
5.5 KiB
Markdown
如何用Perl访问SQLite数据库
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================================================================================
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SQLite是一个零配置、无服务端、基于文件的事务型数据库系统。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是一个非常不错的选择。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。
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### 访问SQLite的准备 ###
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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）。
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**Debian、 Ubuntu 或者 Linux Mint**
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$ sudo apt-get install sqlite3 libdbd-sqlite3-perl
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**CentOS、 Fedora 或者 RHEL**
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$ sudo yum install sqlite perl-DBD-SQLite
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安装后，你可以检查SQLite驱动可以通过下面的脚本访问到。
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#!/usr/bin/perl
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my @drv = DBI->available_drivers();
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print join("\n", @drv), "\n";
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如果你运行脚本，你应该会看见下面的输出。
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DBM
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ExampleP
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File
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Gofer
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Proxy
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SQLite
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Sponge
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### Perl SQLite 访问示例 ###
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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
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- 在表中删除行
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-
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use DBI;
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use strict;
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# 定义数据库名称和驱动
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my $driver = "SQLite";
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my $db_name = "xmodulo.db";
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my $dbd = "DBI:$driver:dbname=$db_name";
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# sqlite 没有用户名密码的概念
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my $username = "";
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my $password = "";
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# 创建并连接到数据库
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# 以下创建的文件名为 xmodulo.db
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my $dbh = DBI->connect($dbd, $username, $password, { RaiseError => 1 })
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or die $DBI::errstr;
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print STDERR "Database opened successfully\n";
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# 创建表
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my $stmt = qq(CREATE TABLE IF NOT EXISTS NETWORK
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(ID INTEGER PRIMARY KEY AUTOINCREMENT,
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HOSTNAME TEXT NOT NULL,
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IPADDRESS INT NOT NULL,
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OS CHAR(50),
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CPULOAD REAL););
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my $ret = $dbh->do($stmt);
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if($ret < 0) {
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print STDERR $DBI::errstr;
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} else {
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print STDERR "Table created successfully\n";
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}
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# 插入三行到表中
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$stmt = qq(INSERT INTO NETWORK (HOSTNAME,IPADDRESS,OS,CPULOAD)
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VALUES ('xmodulo', 16843009, 'Ubuntu 14.10', 0.0));
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$ret = $dbh->do($stmt) or die $DBI::errstr;
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$stmt = qq(INSERT INTO NETWORK (HOSTNAME,IPADDRESS,OS,CPULOAD)
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VALUES ('bert', 16843010, 'CentOS 7', 0.0));
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$ret = $dbh->do($stmt) or die $DBI::errstr;
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$stmt = qq(INSERT INTO NETWORK (HOSTNAME,IPADDRESS,OS,CPULOAD)
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VALUES ('puppy', 16843011, 'Ubuntu 14.10', 0.0));
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$ret = $dbh->do($stmt) or die $DBI::errstr;
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# 在表中检索行
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$stmt = qq(SELECT id, hostname, os, cpuload from NETWORK;);
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my $obj = $dbh->prepare($stmt);
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$ret = $obj->execute() or die $DBI::errstr;
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if($ret < 0) {
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print STDERR $DBI::errstr;
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}
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while(my @row = $obj->fetchrow_array()) {
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print "ID: ". $row[0] . "\n";
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print "HOSTNAME: ". $row[1] ."\n";
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print "OS: ". $row[2] ."\n";
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print "CPULOAD: ". $row[3] ."\n\n";
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}
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# 更新表中的某行
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$stmt = qq(UPDATE NETWORK set CPULOAD = 50 where OS='Ubuntu 14.10';);
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$ret = $dbh->do($stmt) or die $DBI::errstr;
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if( $ret < 0 ) {
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print STDERR $DBI::errstr;
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} else {
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print STDERR "A total of $ret rows updated\n";
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}
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# 从表中删除某行
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$stmt = qq(DELETE from NETWORK where ID=2;);
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$ret = $dbh->do($stmt) or die $DBI::errstr;
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if($ret < 0) {
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print STDERR $DBI::errstr;
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} else {
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print STDERR "A total of $ret rows deleted\n";
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}
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# 断开数据库连接
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$dbh->disconnect();
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print STDERR "Exit the database\n";
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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。
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Database opened successfully
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Table created successfully
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ID: 1
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HOSTNAME: xmodulo
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OS: Ubuntu 14.10
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CPULOAD: 0
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ID: 2
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HOSTNAME: bert
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OS: CentOS 7
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CPULOAD: 0
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ID: 3
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HOSTNAME: puppy
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OS: Ubuntu 14.10
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CPULOAD: 0
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A total of 2 rows updated
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A total of 1 rows deleted
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Exit the database
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### 错误定位 ###
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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。
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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.
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BEGIN failed--compilation aborted at ./script.pl line 3.
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--------------------------------------------------------------------------------
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via: http://xmodulo.com/access-sqlite-database-perl.html
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作者：[Dan Nanni][a]
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译者：[geekpi](https://github.com/geekpi)
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校对：[wxy](https://github.com/wxy)
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本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创翻译，[Linux中国](https://linux.cn/) 荣誉推出
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[a]:http://xmodulo.com/author/nanni
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