SQLite – Perl

安裝

SQLite3 可使用Perl DBI 模塊與Perl 進行集成。 Perl DBI 模塊是Perl 編程語言的數據庫訪問模塊。它定義了一組提供標準數據庫接口的方法、變量及規則。

下面顯示了在Linux/UNIX 機器上安裝DBI 模塊的簡單步驟：

$ 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

如果您需要為DBI 安裝SQLite 驅動程序，那麼可按照以下步驟進行安裝：

$ 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

以下是重要的DBI 程序，可以滿足您在Perl 程序中使用SQLite 數據庫的需求。如果您需要了解更多細節，請查看Perl DBI 官方文檔。

序号	API & 描述
1	DBI->connect($data_source, "", "", \%attr) 建立一个到被请求的 $data_source 的数据库连接或者 session。如果连接成功，则返回一个数据库处理对象。数据源形式如下所示：DBI:SQLite:dbname='test.db'。其中，SQLite 是 SQLite 驱动程序名称，test.db 是 SQLite 数据库文件的名称。如果文件名filename赋值为':memory:'，那么它将会在 RAM 中创建一个内存数据库，这只会在 session 的有效时间内持续。如果文件名 filename 为实际的设备文件名称，那么它将使用这个参数值尝试打开数据库文件。如果该名称的文件不存在，那么将创建一个新的命名为该名称的数据库文件。您可以保留第二个和第三个参数为空白字符串，最后一个参数用于传递各种属性，详见下面的实例讲解。
2	$dbh->do($sql) 该例程准备并执行一个简单的 SQL 语句。返回受影响的行数，如果发生错误则返回 undef。返回值 -1 意味着行数未知，或不适用，或不可用。在这里，$dbh 是由 DBI->connect() 调用返回的处理。
3	$dbh->prepare($sql) 该例程为数据库引擎后续执行准备一个语句，并返回一个语句处理对象。
4	$sth->execute() 该例程执行任何执行预准备的语句需要的处理。如果发生错误则返回 undef。如果成功执行，则无论受影响的行数是多少，总是返回 true。在这里，$sth 是由 $dbh->prepare($sql) 调用返回的语句处理。
5	$sth->fetchrow_array() 该例程获取下一行数据，并以包含各字段值的列表形式返回。在该列表中，Null 字段将作为 undef 值返回。
6	$DBI::err 这相当于 $h->err。其中，$h 是任何的处理类型，比如 $dbh、$sth 或 $drh。该程序返回最后调用的驱动程序（driver）方法的数据库引擎错误代码。
7	$DBI::errstr 这相当于 $h->errstr。其中，$h 是任何的处理类型，比如 $dbh、$sth 或 $drh。该程序返回最后调用的 DBI 方法的数据库引擎错误消息。
8	$dbh->disconnect() 该例程关闭之前调用 DBI->connect() 打开的数据库连接。

連接數據庫

下面的Perl 代碼顯示瞭如何連接到一個現有的數據庫。如果數據庫不存在，那麼它就會被創建，最後將返回一個數據庫對象。

#!/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\n";

現在，讓我們來運行上面的程序，在當前目錄中創建我們的數據庫test.db 。 您可以根據需要改變路徑。保存上面代碼到sqlite.pl 文件中，並按如下所示執行。如果數據庫成功創建，那麼會顯示下面所示的消息：

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

創建表

下面的Perl 代碼段將用於在先前創建的數據庫中創建一個表：

#!/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\n";

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\n";
}
$dbh->disconnect();

上述程序執行時，它會在test.db中創建COMPANY表，並顯示下面所示的消息：

Opened database successfully
Table created successfully

注意：如果您在任何操作中遇到了下面的錯誤： in case you see following error in any of the operation:

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

在這種情況下，您已經在DBD-SQLite安裝中打開了可用的dbdimp.c文件，找到sqlite3_prepare()函數，並把它的第三個參數0改為-1。 最後使用make和make install安裝DBD::SQLite，即可解決問題。 in this case you will have open dbdimp.c file available in DBD-SQLite installation and find outsqlite3_prepare() function and change its third argument to -1 instead of 0. Finally install DBD::SQLite using makeand domake installto resolve the problem.

INSERT 操作

下面的Perl 程序顯示瞭如何在上面創建的COMPANY 表中創建記錄：

#!/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\n";

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\n";
$dbh->disconnect();

上述程序執行時，它會在COMPANY 表中創建給定記錄，並會顯示以下兩行：

Opened database successfully
Records created successfully

SELECT 操作

下面的Perl 程序顯示瞭如何從前面創建的COMPANY 表中獲取並顯示記錄：

#!/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\n";

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] . "\n";
      print "NAME = ". $row[1] ."\n";
      print "ADDRESS = ". $row[2] ."\n";
      print "SALARY = ". $row[3] ."\n\n";
}
print "Operation done successfully\n";
$dbh->disconnect();

上述程序執行時，它會產生以下結果：

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

下面的Perl 代碼顯示瞭如何使用UPDATE 語句來更新任何記錄，然後從COMPANY 表中獲取並顯示更新的記錄：

#!/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\n";

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\n";
}
$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] . "\n";
      print "NAME = ". $row[1] ."\n";
      print "ADDRESS = ". $row[2] ."\n";
      print "SALARY = ". $row[3] ."\n\n";
}
print "Operation done successfully\n";
$dbh->disconnect();

上述程序執行時，它會產生以下結果：

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

下面的Perl 代碼顯示瞭如何使用DELETE 語句刪除任何記錄，然後從COMPANY 表中獲取並顯示剩餘的記錄：

#!/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\n";

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\n";
}
$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] . "\n";
      print "NAME = ". $row[1] ."\n";
      print "ADDRESS = ". $row[2] ."\n";
      print "SALARY = ". $row[3] ."\n\n";
}
print "Operation done successfully\n";
$dbh->disconnect();

上述程序執行時，它會產生以下結果：

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

上一頁： SQLite – PHP

下一頁： SQLite – Python

SQlite 教程

SQLite 高級教程

SQLite 接口

SQLite – Perl

安裝

DBI 接口API

連接數據庫

創建表

INSERT 操作

SELECT 操作

UPDATE 操作

DELETE 操作