Tangram::Type - mapping individual fields
Tangram's persistent type system is extensible, allowing you to mount your own types and make them persistent. All you have to do is to register your type and provide mapping code. See the Tangram::Type::Extending manpage.
Tangram comes with built-in support for the following types:
Supported are strings, integers, real numbers and dates. More types of this ilk are easily added.
string, int, real: see the Tangram::Type::Scalar manpage
date, time, datetime, dmdatetime: see Date/Type/Date/DateTime in the Tangram::Type manpage
perl_dump: see the Tangram::Type::Dump::Perl manpage. A perl_dump structure may
contain any structure which Data::Dumper can dump successfully.
storable: see the Tangram::Type::Dump::Storable manpage. Very much like perl_dump,
but implemented via the `Storable' serialisation engine.
yaml: see the Tangram::Type::Dump::YAML manpage. Very much like perl_dump, but
implemented via the `YAML' serialisation engine. Doesn't currently
work, due to inadequacies in the current Perl YAML implementation.
NEW in Tangram 2.08:
idbif: see the Tangram::Type::Dump::Any manpage. Like the above, but can combine
multiple object properties into a single database column.
Note: these are only actually required if you need to be able to query
on individual fields inside the array/hash - otherwise, the
perl_dump or idbif mapping is a lot faster and more flexible.
flat_array: see Array/Scalar in the Tangram::Type manpage
flat_hash: see Hash/Scalar in the Tangram::Type manpage
ref: see the Tangram::Type::Ref::FromMany manpage (implementing an N to 1 relationship,
in which any object can be the referant)
Set relationships are closest to the main type of relationship used in an RDBMS. Avid CompSci students will know that the relational database model is based heavily on `Set Theory', which is a subset of a more general concept of `Categories' - generic couplings of a number of classes.
In Perl space, these collections are represented via the Set::Object module. Sets may not have duplicate elements, and cannot contain undef values.
set: see the Tangram::Type::Set::FromMany manpage (implementing an unordered N to N
relationship, with all objects sharing a common base class)
iset: see the Tangram::Type::Set::FromOne manpage (implementing an unordered 1 to
N relationship, with all objects sharing a common base class)
The addition to Sets, you can have `Arrays' of objects, represented by
a standard Perl array in memory. Arrays may contain undef values
(in the middle of the list), and the array type may contain
duplicates (ie, the same element present in seperate places in the
list).
array : see the Tangram::Type::Array::FromMany manpage (implementing an ordered N to N
relationship, with all objects sharing a common base class)
iarray: see the Tangram::Type::Array::FromOne manpage (implementing an ordered 1
to N relationship, with all objects sharing a common base class)
Much like the Array types, the Hash types are indexed via a string
value, and represented as a Perl hash in memory. These hashes may not
contain undef values (those are dropped). The hash type may
contain duplicate elements.
hash : see the Tangram::Type::Hash::FromMany manpage (implementing a keyed N to N
relationship, with all objects sharing a common base class)
ihash: see the Tangram::Type::Hash::FromOne manpage (implementing a keyed 1 to N
relationship, with all objects sharing a common base class)