安装
PostgreSQL可以用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,Linux/Unix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的驱动,那么它可以被安装如下:
- $ 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
在开始使用Perl的PostgreSQL的接口,需要在PostgreSQL安装目录中找到pg_hba.conf文件,并添加下面一行:
- # IPv4 local connections:
- host all all 127.0.0.1/32 md5
可以使用下面的命令启动/重新启动Postgres的服务器的如果它没有运行:
- [root@host]# service postgresql restart
- Stopping postgresql service: [ OK ]
- Starting postgresql service: [ OK ]
DBI 接口APIs
以下是重要的DBI例程,可以根据要求使用Perl程序操作SQLite数据库。如果更复杂的应用程序,那么可以看看到的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 = "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";
现在让我们运行上面的程序来打开我们的数据库testdb中,如果成功打开数据库,然后它会给下面的消息:
- Open database successfully
#p#
创建表
下面的Perl程序将在以前创建的数据库中创建一个表:
- #!/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();
上述程序执行时,它会在数据库testdb 创建COMPANY 表公司,它会显示以下消息:
- Opened database successfully
- Table created successfully
INSERT 操作
Perl程序,显示我们如何在上面的例子中创建COMPANY 表中的记录:
- #!/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();
上述程序执行时,它会创建COMPANY表中的记录,并会显示以下两行:
- Opened database successfully
- Records created successfully
SELECT 操作
Perl程序,表明我们如何获取并显示在上面的例子中创建表COMPANY 中的记录:
- #!/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();
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
#p#
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,然后从COMPANY 表获取并显示更新的记录:
- #!/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();
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代码显示了我们如何使用DELETE语句删除任何记录,然后获取COMPANY 表并显示剩余记录 :
- #!/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();
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
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