PostgreSQL可以使用perldbi模塊與Perl集成，perldbi模塊是Perl編程語言的數(shù)據(jù)庫訪問模塊。它定義了一組提供標準數(shù)據(jù)庫接口的方法、變量和約定。
下面是在您的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，那么可以按照以下方式安裝它
$ wget http://search.cpan.org/CPAN/authors/id/T/TU/TURNSTEP/DBD-Pg-2.19.3.tar.gz $ tar xvfz DBD-Pg-2.19.3.tar.gz $ cd DBD-Pg-2.19.3 $ perl Makefile.PL $ make $ make install
在開始使用Perl PostgreSQL接口之前，在PostgreSQL安裝目錄下找到pg_hba.conf文件，添加下面一行
# IPv4 local connections: host all all 127.0.0.1/32 md5
如果postgres服務器沒有運行，可以使用以下命令啟動/重新啟動postgres服務器-
[root@host]# service postgresql restart Stopping postgresql service: [ OK ] Starting postgresql service: [ OK ]
下面是一些重要的DBI例程，它們可以滿足您在Perl程序中使用SQLite數(shù)據(jù)庫的需求。如果您正在尋找更復雜的應用程序，那么您可以查看Perl DBI官方文檔。
| S. No. | API & Description |
|---|---|
| 1 | DBI→connect($data_source, "userid", "password", \%attr) 建立到請求的$data_source的數(shù)據(jù)庫連接或會話。如果連接成功，返回一個數(shù)據(jù)庫句柄對象。 Datasource 格式為: DBI:Pg:dbname=$database;host=127.0.0.1;port=5432 Pg是PostgreSQL驅動程序名，testdb是數(shù)據(jù)庫名。 |
| 2 | $dbh→do($sql) 這個例程準備并執(zhí)行一個 SQL 語句。返回錯誤時受影響或未定義的行數(shù)。返回值-1表示行數(shù)不知道、不適用或不可用。這里 $dbh 是 DBI → connect ()調用返回的句柄。 |
| 3 | $dbh→prepare($sql) 準備一個語句供數(shù)據(jù)庫引擎稍后執(zhí)行，并返回對語句句柄對象的引用。 |
| 4 | $sth→execute() 執(zhí)行執(zhí)行準備好的語句所需的任何處理。如果發(fā)生錯誤，則返回undef。無論受影響的行數(shù)是多少，成功執(zhí)行總是返回true。這里的$sth是一個由$dbh→prepare($sql)調用返回的語句句柄。 |
| 5 | $sth→fetchrow_array() 獲取下一行數(shù)據(jù)，并將其作為包含字段值的列表返回?？兆侄卧诹斜碇凶鳛閡ndef值返回。 |
| 6 | $DBI::err 相當于$h→err，其中$h是任何句柄類型，如$dbh、$sth或$drh。這將從上次調用的驅動程序方法返回本機數(shù)據(jù)庫引擎錯誤代碼。 |
| 7 | $DBI::errstr 相當于$h→errstr，其中$h是任何句柄類型，如$dbh、$sth或$drh。這將從上次調用的DBI方法返回本機數(shù)據(jù)庫引擎錯誤消息。 |
| 8 | $dbh->disconnect() 關閉了之前通過調用DBI→connect()打開的數(shù)據(jù)庫連接。 |
下面的Perl代碼展示了如何連接到現(xiàn)有數(shù)據(jù)庫。如果數(shù)據(jù)庫不存在，那么將創(chuàng)建它，最后將返回一個數(shù)據(jù)庫對象。
#!/usr/bin/perl
use DBI;
use strict;
my $driver = "Pg";
my $database = "testdb";
my $dsn = "DBI:$driver:dbname = $database;host = 127.0.0.1;port = 5432";
my $userid = "postgres";
my $password = "pass123";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 })
or die $DBI::errstr;
print "Opened database successfully\n";現(xiàn)在，讓我們運行上面給定的程序來打開數(shù)據(jù)庫testdb；如果數(shù)據(jù)庫成功打開，那么它將給出以下消息-
Open database successfully
下面的Perl程序將用于在先前創(chuàng)建的數(shù)據(jù)庫中創(chuàng)建表
#!/usr/bin/perl
use DBI;
use strict;
my $driver = "Pg";
my $database = "testdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=5432";
my $userid = "postgres";
my $password = "pass123";
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();當執(zhí)行上面給定的程序時，它將在 testdb 中創(chuàng)建 COMPANY 表，并顯示以下消息-
Opened database successfully Table created successfully
下面的Perl程序顯示了如何在上面示例中創(chuàng)建的COMPANY表中創(chuàng)建記錄-
#!/usr/bin/perl
use DBI;
use strict;
my $driver = "Pg";
my $database = "testdb";
my $dsn = "DBI:$driver:dbname = $database;host = 127.0.0.1;port = 5432";
my $userid = "postgres";
my $password = "pass123";
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();當上述程序執(zhí)行時，將在COMPANY表中創(chuàng)建給定的記錄，并顯示以下兩行
Opened database successfully Records created successfully
下面的Perl程序顯示了如何從上面示例中創(chuàng)建的COMPANY表中獲取和顯示記錄-
#!/usr/bin/perl
use DBI;
use strict;
my $driver = "Pg";
my $database = "testdb";
my $dsn = "DBI:$driver:dbname = $database;host = 127.0.0.1;port = 5432";
my $userid = "postgres";
my $password = "pass123";
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();當上述程序執(zhí)行時，會產生如下結果
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
下面的Perl代碼展示了如何使用UPDATE語句更新任何記錄，然后從我們的COMPANY表中獲取并顯示更新后的記錄：
#!/usr/bin/perl
use DBI;
use strict;
my $driver = "Pg";
my $database = "testdb";
my $dsn = "DBI:$driver:dbname = $database;host = 127.0.0.1;port = 5432";
my $userid = "postgres";
my $password = "pass123";
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();當上述程序執(zhí)行時，會產生如下結果
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
下面的 Perl 代碼展示了如何使用 DELETE 語句刪除任何記錄，然后從 COMPANY 表-中獲取并顯示剩余的記錄
#!/usr/bin/perl
use DBI;
use strict;
my $driver = "Pg";
my $database = "testdb";
my $dsn = "DBI:$driver:dbname = $database;host = 127.0.0.1;port = 5432";
my $userid = "postgres";
my $password = "pass123";
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();當上述程序執(zhí)行時，會產生如下結果
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