NAME

SQL::Type::Guess - guess an appropriate column type for a set of data

SYNOPSIS

my @data=(
  { seen => 1, when => '20140401', greeting => 'Hello', value => '1.05'  },
  { seen => 0, when => '20140402', greeting => 'World', value => '99.05' },
  { seen => 0, when => '20140402', greeting => 'World', value => '9.005' },
);

my $g= SQL::Type::Guess->new();
$g->guess( @data );

print $g->as_sql( table => 'test' );
# create table test (
#    "seen" decimal(1,0),
#    "greeting" varchar(5),
#    "value" decimal(5,3),
#    "when" date
# )

METHODS

SQL:::Type::Guess->new( %OPTIONS )

my $g= SQL::Type::Guess->new();

Creates a new SQL::Type::Guess instance. The following options are supported:

• column_type

  Hashref of already known column types.

• column_map

  Hashref mapping the combinations SQL type names to the resulting type name.

$g->column_type

$g->guess({ foo => 1, bar => 'Hello' },{ foo => 1000, bar => 'World' });
print $g->column_type->{ 'foo' } # decimal(4,0)

Returns a hashref containing the SQL types to store all values in the columns seen so far.

$g->column_map

Returns the hashref used for the type transitions. The current transitions used for generalizing data are:

date -> decimal -> varchar

This is not entirely safe, as 2014-01-01 can't be safely loaded into an decimal column, but assuming your data is representative of the data to be stored that shouldn't be much of an issue.

$g->guess_data_type $OLD_TYPE, @VALUES

$type= $g->guess_data_type( $type, 1,2,3,undef,'Hello','World', );

Returns the data type that encompasses the already established data type in $type and the new values as passed in via @values.

If there is no preexisting data type, $type can be undef or the empty string.

$g->guess( @RECORDS )

my @data= (
    { rownum => 1, name => 'John Smith', street => 'Nowhere Road', birthday => '1996-01-01' },
    { rownum => 2, name => 'John Doe', street => 'Anywhere Plaza', birthday => '1904-01-01' },
    { rownum => 3, name => 'John Bull', street => 'Everywhere Street', birthday => '2001-09-01' },
);
$g->guess( @data );

Modifies the data types for the keys in the given hash.

$g->as_sql %OPTIONS

print $g->as_sql();

Returns an SQL string that describes the data seen so far.

Options:

• user

  Supply a username for the table

• columns

  This allows you to specify the columns and their order. The default is alphabetical order of the columns.

BUG TRACKER

Please report bugs in this module via the RT CPAN bug queue at https://rt.cpan.org/Public/Dist/Display.html?Name=SQL-Type-Guess or via mail to sql-type-guess-Bugs@rt.cpan.org.

AUTHOR

Max Maischein corion@cpan.org

COPYRIGHT (c)

Copyright 2014-2018 by Max Maischein corion@cpan.org.

LICENSE

This module is released under the same terms as Perl itself.