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Perl訪問(wèn)MSSQL并遷移到MySQL數(shù)據(jù)庫(kù)腳本實(shí)例

2020-10-31 15:16:40
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Linux下沒(méi)有專(zhuān)門(mén)為MSSQL設(shè)計(jì)的訪問(wèn)庫(kù),不過(guò)介于MSSQL本是從sybase派生出來(lái)的,因此用來(lái)訪問(wèn)Sybase的庫(kù)自然也能訪問(wèn)MSSQL,F(xiàn)reeTDS就是這么一個(gè)實(shí)現(xiàn)。
Perl中通常使用DBI來(lái)訪問(wèn)數(shù)據(jù)庫(kù),因此在系統(tǒng)安裝了FreeTDS之后,可以使用DBI來(lái)通過(guò)FreeTDS來(lái)訪問(wèn)MSSQL數(shù)據(jù)庫(kù),例子:

復(fù)制代碼 代碼如下:

using DBI;
my $cs = "DRIVER={FreeTDS};SERVER=主機(jī);PORT=1433;DATABASE=數(shù)據(jù)庫(kù);UID=sa;PWD=密碼;TDS_VERSION=7.1;charset=gb2312";
my $dbh = DBI->connect("dbi:ODBC:$cs") or die $@;

因?yàn)楸救瞬辉趺从脀indows,為了研究QQ群數(shù)據(jù)庫(kù),需要將數(shù)據(jù)從MSSQL中遷移到MySQL中,特地為了QQ群數(shù)據(jù)庫(kù)安裝了一個(gè)Windows Server 2008和SQL Server 2008r2,不過(guò)過(guò)幾天評(píng)估就到期了,研究過(guò)MySQL的Workbench有從MS SQL Server遷移數(shù)據(jù)的能力,不過(guò)對(duì)于QQ群這種巨大數(shù)據(jù)而且分表分庫(kù)的數(shù)據(jù)來(lái)說(shuō)顯得太麻煩,因此寫(xiě)了一個(gè)通用的perl腳本,用來(lái)將數(shù)據(jù)庫(kù)從MSSQL到MySQL遷移,結(jié)合bash,很方便的將這二十多個(gè)庫(kù)上百?gòu)埍斫o轉(zhuǎn)移過(guò)去了,Perl代碼如下:
復(fù)制代碼 代碼如下:

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


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

print "Connectin to databases $db.../n";
my $cs = "DRIVER={FreeTDS};SERVER=MSSQL的服務(wù)器;PORT=1433;DATABASE=$db;UID=sa;PWD=MSSQL密碼;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服務(wù)器", "MySQL用戶名", "MySQL密碼") 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';");#獲取所有表名
my $q_key_usage = $src->prepare("SELECT TABLE_NAME, COLUMN_NAME from INFORMATION_SCHEMA.KEY_COLUMN_USAGE;");#獲取表的主鍵
$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;


#獲取表的索引信息
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;

#在目標(biāo)MySQL上創(chuàng)建對(duì)應(yīng)的數(shù)據(jù)庫(kù)
$target->do("DROP DATABASE IF EXISTS `$db`;") or die "Cannot drop old database $db/n";
$target->do("CREATE DATABASE `$db` DEFAULT CHARSET = utf8 COLLATE utf8_general_ci;") or die "Cannot create database $db/n";
$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;");
        #獲取表結(jié)構(gòu),用來(lái)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;/n/n";
        $target->do($ddl) or die "Cannot create table $table/n";
        #創(chuàng)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";
            }
        }
        #轉(zhuǎn)移數(shù)據(jù)
        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;");
        #結(jié)束,輸出任務(wù)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 processes/n";
#等待所有子進(jìn)程結(jié)束
while (wait() != -1) {}
my $total_elapsed = time - $total_start;
print "All tasks from $db finished, $total_elapsed seconds./n";

這個(gè)腳本會(huì)根據(jù)每一個(gè)表fork出一個(gè)子進(jìn)程和相應(yīng)的數(shù)據(jù)庫(kù)連接,因此做這種遷移之前得確保目標(biāo)MySQL數(shù)據(jù)庫(kù)配置的最大連接數(shù)能承受。
然后在bash下執(zhí)行

復(fù)制代碼 代碼如下:

for x in {1..11};do ./qq.pl QunInfo$x; done
for x in {1..11};do ./qq.pl GroupData$x; done

就不用管了,腳本會(huì)根據(jù)MSSQL這邊表結(jié)構(gòu)來(lái)在MySQL那邊創(chuàng)建一樣的結(jié)構(gòu)并配置索引。

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