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 # Check if a record exists
 exists $hash{$recordKey}

 # Get a field
 $scalar = $hash{$recordKey}{$fieldName};

 # Assign to a field
 $hash{$recordKey}{$fieldName} = $value; 

=head1 DESCRIPTION

The B<AsciiDB::TagFile> provides a hash-table-like interface to a simple ASCII
database.

The ASCII database stores each record in into a file:

	$directory/recordKey1$sufix
	$directory/recordKey2$sufix
	...
	$directory/recordKeyI<N>$sufix

And a record has this format:

	[fieldName1]: value1
	[fieldName2]: value2
	...
	[fieldNameI<N>]: value2

After you've tied the hash you can access this database as access a hash of 
hashes:

	$hash{recordKey1}{fieldName1} = ...

To bind the %hash to the class AsciiDB::TagFile you have to use the tie
function:

	tie %hash, 'AsciiDB::TagFile', PARAM1 => $param1, ...;

The parameters are:

=over 4

=item DIRECTORY

The directory where the records will be stored or readed from.
The default value is the current directory.

=item SUFIX

The records are stored as files. The file name of a record is the
key plus this sufix (if supplied).

For example, if the record with key 'josear' and sufix '.record', will
be stored into file: 'josear.record'.

If this parameter is not supplied the records won't have a sufix.

=item LOCK

If you set this parameter to 1 TagFile will perform basic locking.
Record files will be share locked before reading them, and exclusive
locked when syncing (writing) them.

This basic locking only guarantees that a record file is always
written correctly, but as TagFile keep records in memory you can still suffer
consistency problems reading fields.

The default value is 0, i.e. the database won't be locked.

=item READONLY

If you set this parameter to 1 the database will be read only and
all changes will be discarted.

The default value is 0, i.e. the database can be changed.

=item CACHESIZE

Records loaded from disk (or simply created) are keeped in memory till
the tied hash is deleted. You can limit the number of records in memory
setting this option to a value ($cacheSize).

All records are purged from memory if their count reach $cacheSize.

You can purge the records manually using the purge() method.

Of course, the $caseSize should be a positive number, and you can use
the 0 value to turn off the caching (useful when testing).
 
The default value for CACHESIZE is 'infinite' (more or less...)

=item FILEMODE

Filemode assigned to new created files. 

If this parameter is not supplied the new created files will have the
default permissions.

=item SCHEMA

This parameter is a hash reference that contains the database definition.

With ORDER you can specify in which order fields will be saved into the
file.

For example,

 SCHEMA => {
	ORDER => [ 'fieldHi', 'field2There', 'fieldWorld' ]
 }

will save the record this way:

	[fieldHi]: ...
	[fieldThere]: ...
	[fieldWorld]: ...

NOTE: this parameter is MANDATORY, and you have to specify all the
fields. B<If you forget to list a field it will not be saved>.

With KEY,ENCODE and KEY,DECODE you can define an special encoding
for keys when used as filenames.

For example, if using this SCHEMA:

 SCHEMA => {
         ORDER => ['a', 'b', 'c'],
         KEY => {