Perl访问MSSQL并迁移到MySQL数据库脚本实例实用指南

die "Usage: qq dbn" if @ARGV != 1;
my $db = $ARGV[0];

print "Connectin to databases $db...n";
my $cs = "DRIVER={FreeTDS};SERVER=MSSQL的服务器;PORT=1433;DATABASE=$db;UID=sa;PWD=MSSQL密码;TDS_VERSION=7.1;charset=gb2312";

sub db_connect
{
my $src = DBI->connect("dbi:ODBC:$cs") or die $@;
my $target = DBI->connect("dbi:mysql:host=MySQL服务器", "MySQL用户名", "MySQL密码") or die $@;
return ($src, $target);
}
my ($src, $target) = db_connect;

print "Reading table schemas....n";

my $q_tables = $src->prepare("SELECT name FROM sysobjects WHERE xtype = 'U' AND name != 'dtproperties';");#拿到所有表名
my $q_key_usage = $src->prepare("SELECT TABLE_NAME, COLUMN_NAME from INFORMATION_SCHEMA.KEY_COLUMN_USAGE;");#拿到表的主键
$q_tables->execute;
my @tables = ();
my %keys = ();
push @tables, @_ while @_ = $q_tables->fetchrow_array;

$q_tables->finish;

$q_key_usage->execute();
$keys{$_[0]} = $_[1] while @_ = $q_key_usage->fetchrow_array;
$q_key_usage->finish;

#拿到表的索引信息
my $q_index = $src->prepare(qq(
SELECT T.name, C.name
FROM sys.index_columns I
INNER JOIN sys.tables T ON T.object_id = I.object_id
INNER JOIN sys.columns C ON C.column_id = I.column_id AND I.object_id = C.object_id;
));
$q_index->execute;
my %table_indices = ();
while(my @row = $q_index->fetchrow_array)
{
my ($table, $column) = @row;
my $columns = $table_indices{$table};
$columns = $table_indices{$table} = [] if not $columns;
push @$columns, $column;
}
$q_index->finish;

#在目标MySQL上新建对应的数据库
$target->do("DROP DATABASE IF EXISTS `$db`;") or die "Cannot drop old database $dbn";
$target->do("CREATE DATABASE `$db` DEFAULT CHARSET = utf8 COLLATE utf8_general_ci;") or die "Cannot create database $dbn";
$target->disconnect;
$src->disconnect;

my $total_start = time;
for my $table(@tables)
{
my $pid = fork;
unless($pid)
{
($src, $target) = db_connect;
my $start = time;
$src->do("USE $db;");
#拿到表结构，用来生成MySQL用的DDL
my $q_schema = $src->prepare("SELECT COLUMN_NAME, IS_NULLABLE, DATA_TYPE, CHARACTER_MAXIMUM_LENGTH from INFORMATION_SCHEMA.COLUMNS where TABLE_NAME = ? ORDER BY ORDINAL_POSITION;");
$target->do("USE `$db`;");
$target->do("SET NAMES utf8;");
my $key_column = $keys{$table};
my $ddl = "CREATE TABLE `$table` ( n";
$q_schema->execute($table);
my @fields = ();
while(my @row = $q_schema->fetchrow_array)
{
my ($column, $nullable, $datatype, $length) = @row;
my $field = "`$column` $datatype";
$field .= "($length)" if $length;
$field .= " PRIMARY KEY" if $key_column eq $column;
push @fields, $field;
}
$ddl .= join(",n", @fields);
$ddl .= "n) ENGINE = MyISAM;nn";
$target->do($ddl) or die "Cannot create table $tablen";
#新建索引
my $indices = $table_indices{$table};
if($indices)
{
for(@$indices)
{
$target->do("CREATE INDEX `$_` ON `$table`(`$_`);n") or die "Cannot create index on $db.$table$.$_n";
}
}
#转移数据
my @placeholders = map {'?'} @fields;
my $insert_sql = "INSERT DELAYED INTO $table VALUES(" .(join ', ', @placeholders) . ");n";
my $insert = $target->prepare($insert_sql);
my $select = $src->prepare("SELECT * FROM $table;");
$select->execute;
$select->{'LongReadLen'} = 1000;
$select->{'LongTruncOk'} = 1;
$target->do("SET AUTOCOMMIT = 0;");
$target->do("START TRANSACTION;");
my $rows = 0;
while(my @row = $select->fetchrow_array)
{
$insert->execute(@row);
$rows++;
}
$target->do("COMMIT;");
#结束，输出任务信息
my $elapsed = time - $start;
print "Child process $$ for table $db.$table done, $rows records, $elapsed seconds.n";
exit(0);
}
}
print "Waiting for child processesn";
#等待所有子进程结束
while (wait() != -1) {}
my $total_elapsed = time - $total_start;
print "All tasks from $db finished, $total_elapsed seconds.n";