Question

表格如下：

创建表格符号（
SymbolID整数不为空，
PngData BLOB
）;

期待您的协助

Answer 1

这是一种使用Perl可以实现的方法。首先，我将PNG图像加载到数据库中，然后将其提取到文件中以显示它是否有效。

#!/usr/bin/perl
use strict;
use warnings;
use DBI;

my $myfile = "picture.png";
my $dbname = "test.db";
my $data;

# Connect to database
my $dbh = DBI->connect("dbi:SQLite:dbname=$dbname") || die "Cannot open db";

# >8 >8 >8  Cut starting here  >8 >8 >8 >8 >8

# Open the image file
open MYFILE, $myfile  or die "Cannot open file";

# Read in the file
while (<MYFILE>) {
   $data .= $_;
}
close MYFILE;

# Insert image into database
my $sql = "INSERT INTO symbols VALUES (1,?)";
my $sth = $dbh->prepare($sql);
my $numrows = $sth->execute($data);
$sth->finish;

# >8 >8 >8  Cut ending here >8 >8 >8 >8 >8

#Now read it back and save as file
$sql = "SELECT PngData from symbols";
$sth = $dbh->prepare($sql);
$numrows = $sth->execute;

open OUTPUT, ">output.png";
my $ref = $sth->fetchrow_hashref;
my $newdata = $$ref{'PngData'};
print OUTPUT $newdata;
close OUTPUT;
$sth->finish;
$dbh->disconnect;

如果您只想从数据库中提取图像BLOB并将其另存为文件，请使用：

#!/usr/bin/perl
use strict;
use warnings;
use DBI;

my $dbname = "test.db";
my ($sql,$sth,$numrows,$ref,$newdata);

# Connect to database
my $dbh = DBI->connect("dbi:SQLite:dbname=$dbname") || die "Cannot open db";

# Read image and save as file
$sql = "SELECT PngData from symbols";
$sth = $dbh->prepare($sql);
$numrows = $sth->execute;

open OUTPUT, ">output.png";
$ref = $sth->fetchrow_hashref;
$newdata = $$ref{'PngData'};
print OUTPUT $newdata;
close OUTPUT;
$sth->finish;
$dbh->disconnect;

如果您想使用sqlite创建数据库，并使用此代码，请执行以下操作：

sqlite3 test.db "CREATE TABLE symbols(SymbolID integer,PngData BLOB);"

如何从SQLite导出BLOB映像（PNG）到文件或Excel？

1 个答案: