连接数据库测试

本例中展示的为本地连接数据库，如远程连接，需要修改配置文件atlasdb_hba.conf或atlasdb.conf以完成远程连接数据库的配置。

连接数据库

以下Perl代码显示如何连接到现有的数据库。如果数据库不存在，那么它将自动创建，最后将返回一个数据库对象。

# shell
vim connect.pl

# perl
#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "Pg"; 
my $database = "atlasdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=15432";
my $userid = "atlasdb";
my $password = "atlasdb";
my $dbh = DBI->connect($dsn, $userid, $password, { RaiseError => 1 }) 
                      or die $DBI::errstr;

print "Opened database successfully\n";

# shell
perl connect.pl

如果成功打开数据库，将打印如下消息：

Opened database successfully

创建表

以下Perl程序将用于在之前创建的数据库Vastbase E100中创建一个表：

# shell
vim createtbl.pl

# perl
#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "Pg"; 
my $database = "atlasdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=15432";
my $userid = "atlasdb";
my $password = "atlasdb";
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();

# shell
perl createtbl.pl

执行上述程序后，它将在atalsdb中创建一张company表：

并显示如下消息：

Opened database successfully
Table created successfully

INSERT操作

以下Perl程序显示了如何在上述示例中创建的COMPANY表中创建/插入记录：

# shell
vim insert.pl

# perl
#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "Pg"; 
my $database = "atlasdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=15432";
my $userid = "atlasdb";
my $password = "atlasdb";
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();

# shell
perl insert.pl

执行以上程序后，它将在company表中插入给定的记录：

并显示以下两行：

Opened database successfully
Records created successfully

SELECT操作

以下Perl程序显示了如何从上述示例中创建的COMPANY表中获取和显示记录：

# shell
vim select.pl

# perl
#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "Pg"; 
my $database = "atlasdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=15432";
my $userid = "atlasdb";
my $password = "atlasdb";
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();

# shell
perl select.pl

执行上述程序后，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代码显示了如何使用UPDATE语句来更新指定记录，然后从COMPANY表中获取和显示更新的记录：

# shell
vim update.pl

# perl
#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "Pg"; 
my $database = "atlasdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=15432";
my $userid = "atlasdb";
my $password = "atlasdb";
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();

# shell
perl update.pl

执行上述程序后，会产生以下结果：

Opened database successfully
Total number of rows updated : 1
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

ID = 1
NAME = Paul
ADDRESS = California                                        
SALARY =  25000

Operation done successfully

DELETE操作

Perl代码显示了如何使用DELETE语句删除指定记录，然后从COMPANY表中获取并显示剩余的记录：

# shell
vim update.pl

# perl
#!/usr/bin/perl

use DBI;
use strict;

my $driver   = "Pg"; 
my $database = "atlasdb";
my $dsn = "DBI:$driver:dbname=$database;host=127.0.0.1;port=15432";
my $userid = "atlasdb";
my $password = "atlasdb";
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();

# shell
perl delete.pl

执行上述程序后，会产生以下结果：

Opened database successfully
Total number of rows deleted : 1
ID = 3
NAME = Teddy
ADDRESS = Norway                                            
SALARY =  20000

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

ID = 1
NAME = Paul
ADDRESS = California                                        
SALARY =  25000

Operation done successfully