SQLite Perl

SQLite3 用Perl使用Perl DBI模块，这是一个Perl编程语言的数据库访问模块可以集成。它定义了一套方法，变数和约定，提供一个标准的数据库接口。

下面是简单的步骤，在Linux /UNIX的机器上安装DBI模块：

$ wget http://search.cpan.org/CPAN/authors/id/T/TI/TIMB/DBI-1.625.tar.gz
$ tar xvfz DBI-1.625.tar.gz
$ cd DBI-1.625
$ perl Makefile.PL
$ make
$ make install

如果需要安装DBI的SQLite 驱动，那么它可以安装如下：

$ wget http://search.cpan.org/CPAN/authors/id/M/MS/MSERGEANT/DBD-SQLite-1.11.tar.gz
$ tar xvfz DBD-SQLite-1.11.tar.gz
$ cd DBD-SQLite-1.11
$ perl Makefile.PL
$ make
$ make install

DBI 接口API

以下是DBI重要程序，可以满足你的工作要求从Perl程序操作SQLite数据库。如果正在寻找一个更复杂的应用程序，那么可以看看 Perl DBI 官方文档。

连接到数据库

下面的Perl代码显示了如何连接到一个现有的数据库。如果数据库不存在，那么它就会被创建，终于将返回一个数据库对象。

#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "SQLite"; 
my $database = "test.db";
my $dsn = "DBI:$driver:dbname=$database";
my $userid = "";
my $password = "";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 }) 
                      or die $DBI::errstr;

print "Opened database successfully";

现在，让我们运行上面的程序在当前目录中，创建数据库test.db。按要求可以改变你的路径。上面的代码在sqlite.pl文件并执行它，如下图所示。如果数据库创建成功，则它会给下面的消息：

$ chmod +x sqlite.pl
$ ./sqlite.pl
Open database successfully

创建表

下面的Perl程序将使用以前创建的数据库中创建一个表：

#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "SQLite";
my $database = "test.db";
my $dsn = "DBI:$driver:dbname=$database";
my $userid = "";
my $password = "";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
                      or die $DBI::errstr;
print "Opened database successfully";

my $stmt = qq(CREATE TABLE COMPANY
      (ID INT PRIMARY KEY     NOT NULL,
       NAME           TEXT    NOT NULL,
       AGE            INT     NOT NULL,
       ADDRESS        CHAR(50),
       SALARY         REAL););
my $rv = $dbh->do($stmt);
if($rv < 0){
   print $DBI::errstr;
} else {
   print "Table created successfully";
}
$dbh->disconnect();

上述程序执行时，它会创建表公司test.db，它会显示以下消息：

Opened database successfully
Table created successfully

注意：任何操作情况下，看到下面的错误：

DBD::SQLite::st execute failed: not an error(21) at dbdimp.c line 398

在这种情况下，打开 dbdimp.c 的文件可在DBD-SQLite的安装，并找出sqlite3_prepare()函数，改变它的第三个参数为-1，而不是0。最后安装DBD:: SQLite的使用make 和make install 来解决问题。 

INSERT 操作

Perl程序，显示我们如何能够创造COMPANY在上面的例子中创建表中的记录：

#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "SQLite";
my $database = "test.db";
my $dsn = "DBI:$driver:dbname=$database";
my $userid = "";
my $password = "";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
                      or die $DBI::errstr;
print "Opened database successfully";

my $stmt = qq(INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (1, 'Paul', 32, 'California', 20000.00 ));
my $rv = $dbh->do($stmt) or die $DBI::errstr;

$stmt = qq(INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (2, 'Allen', 25, 'Texas', 15000.00 ));
$rv = $dbh->do($stmt) or die $DBI::errstr;

$stmt = qq(INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (3, 'Teddy', 23, 'Norway', 20000.00 ));
$rv = $dbh->do($stmt) or die $DBI::errstr;

$stmt = qq(INSERT INTO COMPANY (ID,NAME,AGE,ADDRESS,SALARY)
      VALUES (4, 'Mark', 25, 'Rich-Mond ', 65000.00 ););
$rv = $dbh->do($stmt) or die $DBI::errstr;

print "Records created successfully";
$dbh->disconnect();

上述程序执行时，它会创建COMPANY表中的记录，并显示以下两行：

Opened database successfully
Records created successfully

SELECT 操作

Perl 程序，表明我们如何能够获取并显示COMPANY 表在上面的例子中创建表的记录：

#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "SQLite";
my $database = "test.db";
my $dsn = "DBI:$driver:dbname=$database";
my $userid = "";
my $password = "";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
                      or die $DBI::errstr;
print "Opened database successfully";

my $stmt = qq(SELECT id, name, address, salary  from COMPANY;);
my $sth = $dbh->prepare( $stmt );
my $rv = $sth->execute() or die $DBI::errstr;
if($rv < 0){
   print $DBI::errstr;
}
while(my @row = $sth->fetchrow_array()) {
      print "ID = ". $row[0] . "";
      print "NAME = ". $row[1] ."";
      print "ADDRESS = ". $row[2] ."";
      print "SALARY =  ". $row[3] ."";
}
print "Operation done successfully";
$dbh->disconnect();

当上述程序执行时，它会产生以下结果：

Opened database successfully
ID = 1
NAME = Paul
ADDRESS = California
SALARY =  20000

ID = 2
NAME = Allen
ADDRESS = Texas
SALARY =  15000

ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY =  20000

ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY =  65000

Operation done successfully

UPDATE 操作

Perl代码显示如何，我们可以使用UPDATE语句来更新任何记录，然后获取并显示更新的记录，从COMPANY 表：

#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "SQLite";
my $database = "test.db";
my $dsn = "DBI:$driver:dbname=$database";
my $userid = "";
my $password = "";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
                      or die $DBI::errstr;
print "Opened database successfully";

my $stmt = qq(UPDATE COMPANY set SALARY = 25000.00 where ID=1;);
my $rv = $dbh->do($stmt) or die $DBI::errstr;
if( $rv < 0 ){
   print $DBI::errstr;
}else{
   print "Total number of rows updated : $rv";
}
$stmt = qq(SELECT id, name, address, salary  from COMPANY;);
my $sth = $dbh->prepare( $stmt );
$rv = $sth->execute() or die $DBI::errstr;
if($rv < 0){
   print $DBI::errstr;
}
while(my @row = $sth->fetchrow_array()) {
      print "ID = ". $row[0] . "";
      print "NAME = ". $row[1] ."";
      print "ADDRESS = ". $row[2] ."";
      print "SALARY =  ". $row[3] ."";
}
print "Operation done successfully";
$dbh->disconnect();

当上述程序执行时，它会产生以下结果：

Opened database successfully
Total number of rows updated : 1
ID = 1
NAME = Paul
ADDRESS = California
SALARY =  25000

ID = 2
NAME = Allen
ADDRESS = Texas
SALARY =  15000

ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY =  20000

ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY =  65000

Operation done successfully

DELETE 操作

Perl代码表明我们如何能够使用DELETE语句删除任何记录，然后获取并显示剩余的记录COMPANY 表： 

#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "SQLite";
my $database = "test.db";
my $dsn = "DBI:$driver:dbname=$database";
my $userid = "";
my $password = "";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
                      or die $DBI::errstr;
print "Opened database successfully";

my $stmt = qq(DELETE from COMPANY where ID=2;);
my $rv = $dbh->do($stmt) or die $DBI::errstr;
if( $rv < 0 ){
   print $DBI::errstr;
}else{
   print "Total number of rows deleted : $rv";
}
$stmt = qq(SELECT id, name, address, salary  from COMPANY;);
my $sth = $dbh->prepare( $stmt );
$rv = $sth->execute() or die $DBI::errstr;
if($rv < 0){
   print $DBI::errstr;
}
while(my @row = $sth->fetchrow_array()) {
      print "ID = ". $row[0] . "";
      print "NAME = ". $row[1] ."";
      print "ADDRESS = ". $row[2] ."";
      print "SALARY =  ". $row[3] ."";
}
print "Operation done successfully";
$dbh->disconnect();

当上述程序执行时，它会产生以下结果：

Opened database successfully
Total number of rows deleted : 1
ID = 1
NAME = Paul
ADDRESS = California
SALARY =  25000

ID = 3
NAME = Teddy
ADDRESS = Norway
SALARY =  20000

ID = 4
NAME = Mark
ADDRESS = Rich-Mond
SALARY =  65000

Operation done successfully