script to convert mysql dump sql file into format that can be imported into sqlite3 db

Question

I have an export SQL file containing tables and data from MySQL and I want to import it into a Sqlite 3 DB.

What is the best way to do that?

Just importing t

Answer 1

I tried some of these scripts that uses sed or awk, but always occurs an error, probably due to the indexes and foreign keys of my MySQL db and the mysqldump options needed.

Then I found the Perl module SQL::Translator "that converts vendor-specific SQL table definitions into other formats..."
This module create all foreign keys and correct the indexes, changing the names if necesssary.

So, I rewrite the shell script, including the dump of the MySQL db. There are two dumps because the script "sqlt" only generates the structure and works fast if the dump has no data. Note that it can be adapted to others conversions suported by the SQL::Translator.

After I posted this shell script I realized that the question is about to convert a MySQL dumpfile, so I did a Perl script that do that, using the module SQL::Translator. In my tests, I used a dumpfile generated without options (mysqldump -u user --password database > dumpfile). I had no problems with character sets.

In other test I had problem with mysql triggers, so I altered the scripts to skip it.

#!/bin/sh
#===============================================================================
#         USAGE: ./mysql2sqlite.sh  
#   DESCRIPTION: Converts MySQL databases to SQLite
#                Triggers are not converted
#  REQUIREMENTS: mysqldump, Perl and module SQL::Translator, SQLite 
#===============================================================================
if [ "$#" = 2 ]; then
    USER="$2"    
else
    echo "Usage: $0  "
    exit
fi
if [ -s $1.db ]; then
    read -p "File <$1.db> exists. Overwrite? [y|n] " ANS
    if [ "$ANS" = "y" ] || [ "$ANS" = "Y" ] ; then
        rm $1.db 
    else 
        echo "*** Aborting..."
        exit
    fi
fi   
# extracts the necessary structure for SQLite:
mysqldump --skip-triggers --skip-add-locks --routines --no-data --compatible=ansi \
    --compact -u $USER --password $1 > /tmp/$1_$$_str.sql
# verify
if [ ! -s /tmp/$1_$$_str.sql ]; then
    echo "*** There are some problem with the dump. Exiting."
    exit
fi
# translates MySQL syntax structure to SQLite using the script "sqlt" of the
# perl module SQL::Translator (that corrects the foreign keys, indexes, etc.)
sqlt -f MySQL -t SQLite --show-warnings /tmp/$1_$$_str.sql \
    1> /tmp/$1_$$.sqlite 2> /tmp/$1_$$_sqlt.log
# verify
if [ ! -s /tmp/$1_$$.sqlite ]; then
    echo "*** There are some problem with the sql translation. Exiting."
    exit
fi
# adds statements to allow to load tables with foreign keys:
echo "PRAGMA foreign_keys=OFF;" >> /tmp/$1_$$.sqlite
echo "BEGIN TRANSACTION;" >> /tmp/$1_$$.sqlite
# extracts the data (simple inserts) without locks/disable keys, 
# to be read in versions of SQLite that do not support multiples inserts:
mysqldump --skip-triggers --no-create-db --no-create-info --skip-add-locks \
    --skip-extended-insert --compatible=ansi --compact -u $USER \
    --password $1 >> /tmp/$1_$$.sqlite
# adds statements to finish the transaction:
echo "COMMIT;" >> /tmp/$1_$$.sqlite
echo "PRAGMA foreign_keys=ON;" >> /tmp/$1_$$.sqlite
# correct single quotes in inserts
perl -pi -e ' if (/^INSERT INTO/) { s/\\'\''/'\'\''/g; } ' /tmp/$1_$$.sqlite
# load the sql file and generate the SQLite db with the same name 
# of the MySQL database
sqlite3 $1.db < /tmp/$1_$$.sqlite 2> /tmp/$1_$$sqlite.errlog
# verify
ERRORS=`cat /tmp/$1_$$sqlite.errlog | wc -l`
if [ $ERRORS = 0 ]; then
    echo "* Conversion complete. Verify the file < $1.db >"
    rm /tmp/$1_$$*
else
    echo "*** There are some problem. Verify the files < /tmp/$1_$$* >"
fi

Here the Perl script to convert a dumpfile in a SQLite database file.

#!/usr/bin/perl 
#===============================================================================
#        USAGE: ./mysql2sqlite.pl 
#  DESCRIPTION: Converts MySQL dumpfile to SQLite database
#               Triggers are not converted
#               The dump must be done with
#               > mysqldump --skip-triggers -u [user] --p [database] > dumpfile
# REQUIREMENTS: Perl and module SQL::Translator, SQLite
#===============================================================================
use strict;
use warnings;
use Carp;
use English qw( -no_match_vars );
use SQL::Translator;
use 5.012;

my $file = $ARGV[0];
my $filedb = $file;
$filedb =~ s/\.*[^.]*$/.db/;
if ( -s $filedb ) { 
    say "*** Ja existe o arquivo < $filedb >. Abandonando...";
    exit;
}
my @stru;
my @data;

open( my $SQLFILE, "<", $file )
    or croak "Can't open $file: $OS_ERROR";
while (<$SQLFILE>) {
    # nao considera linhas com comentarios e lock/unlock/drop
    next if ( /^--/ || /^\/\*/ || /^lock/i || /^unlock/i || /^drop/i );
    # processa os inserts
    if (/^(INSERT.+?)[(]/) {     
        my $ins = $1;            # captura o nome da tabela
        s/\\[']/''/g;            # substitue aspas simples - \'
        s/[)],[(]/);\n$ins(/g;   # divide multiplos inserts
        push( @data, $_ );
    }
    # processa a estrutura
    else { push( @stru, $_ ); }
}
close($SQLFILE);

my $strusql = join( '', @stru );
my $datasql = join( '', @data );
#open( my $STRU,   ">", "stru.sql" ); # to verify the results
#open( my $DATA,  ">", "data.sql" );
#print $STRU  $strusql;
#print $DATA  $datasql;

# here the conversion
my $translator = SQL::Translator->new(
    no_comments       => 0,
    show_warnings     => 0,
    quote_table_names => 1,
    quote_field_names => 1,
    validate          => 1,
);
my $struout = $translator->translate(
    from => 'MySQL',
    to   => 'SQLite',
    data => \$strusql,
    # filename => $file,
) or croak "Error: " . $translator->error;

# define inicio e final da transacao de inserts
my $prgini = "PRAGMA foreign_keys=OFF;\n";
my $traini = "BEGIN TRANSACTION;\n";
my $trafin = "COMMIT;\n";
my $prgfin = "PRAGMA foreign_keys=ON;\n";

#gera o arquivo final sqlite
my $sqlout = join( "\n", $struout, $prgini, $traini, $datasql, $trafin, $prgfin);
open( my $FINAL, ">", "/tmp/final.sql" );
print $FINAL $sqlout;

# Monta o SQLite database
my $log = "/tmp/sqlite.errlog";
my $command = "sqlite3 $filedb < /tmp/final.sql 2> $log";
system($command) == 0 or die "system $command failed: $?";
if ( -s $log ) { 
    say "*** Houve algum problema. Verifique o arquivo < /tmp/sqlite.errlog > "; 
}
else { 
    say "*** Conversao completa. Verifique o arquivo < $filedb > "; 
}