use DBIx::DBStag; my $dbh = DBIx::DBStag->connect("dbi:Pg:dbname=moviedb"); my $sql = q[ SELECT studio.*, movie.*, star.* FROM studio NATURAL JOIN movie NATURAL JOIN movie_to_star NATURAL JOIN star WHERE movie.genre = 'sci-fi' AND star.lastname = 'Fisher' USE NESTING (set(studio(movie(star)))) ]; my $dataset = $dbh->selectall_stag($sql); my @studios = $dataset->get_studio;
# returns nested data that looks like this - # # (studio # (name "20th C Fox") # (movie # (name "star wars") (genre "sci-fi") # (star # (firstname "Carrie")(lastname "Fisher")))))
# iterate through result tree - foreach my $studio (@studios) { printf "STUDIO: %s\n", $studio->get_name; my @movies = $studio->get_movie;
foreach my $movie (@movies) { printf " MOVIE: %s (genre:%s)\n", $movie->get_name, $movie->get_genre; my @stars = $movie->get_star;
foreach my $star (@stars) { printf " STARRING: %s:%s\n", $star->get_firstname, $star->get_lastname; } } }
# manipulate data then store it back in the database my @allstars = $dataset->get("movie/studio/star"); $_->set_fullname($_->get_firstname.' '.$_->get_lastname) foreach(@allstars);
$dbh->storenode($dataset); exit 0;
Or from the command line:
unix> selectall_xml.pl -d 'dbi:Pg:dbname=moviebase' \ 'SELECT * FROM studio NATURAL JOIN movie NATURAL \ JOIN movie_to_star NATURAL JOIN star \ USE NESTING (set(studio(movie(star))))'
Or using a predefined template:
unix> selectall_xml.pl -d moviebase /mdb-movie genre=sci-fi
This module is for mapping between relational databases and Stag objects (Structured Tags - see Data::Stag). Stag objects can also be represented as \s-1XML\s0. The module has two main uses:
This module can take the results of any \s-1SQL\s0 query and decompose the flattened results into a tree data structure which reflects the foreign keys in the underlying relational schema. It does this by looking at the \s-1SQL\s0 query and introspecting the database schema, rather than requiring metadata or an object model. In this respect, the module works just like a regular \s-1DBI\s0 handle, with a few extra methods. Queries can also make use of predefined templates
DBStag objects can store any tree-like datastructure (such as \s-1XML\s0 documents) into a database using normalized schema that reflects the structure of the tree being stored. This is done using little or no metadata. \s-1XML\s0 can also be imported, and a relational schema automatically generated.
For a tutorial on using DBStag to build and query relational databases from \s-1XML\s0 sources, please see DBIx::DBStag::Cookbook
This is a general overview of the rules for turning \s-1SQL\s0 query results into a tree like data structure. You don't need to understand all these rules to be able to use this module - you can experiment by using the selectall_xml.pl script which comes with this distribution.
Mapping Relations
Relations (i.e. tables and views) are elements (nodes) in the tree. The elements have the same name as the relation in the database.
These nodes are always non-terminal (ie they always have child nodes)
Mapping Columns
Table and view columns of a relation are sub-elements of the table or view to which they belong. These elements will be data elements (i.e. terminal nodes). Only the columns selected in the \s-1SQL\s0 query will be present.
For example, the following query
SELECT name, job FROM person;
will return a data structure that looks like this:
(set (person (name "fred") (job "forklift driver")) (person (name "joe") (job "steamroller mechanic")))
The data is shown as a lisp-style S-Expression - it can also be expressed as \s-1XML\s0, or manipulated as an object within perl.
Handling table aliases
If an \s-1ALIAS\s0 is used in the \s-1FROM\s0 part of the \s-1SQL\s0 query, the relation element will be nested inside an element with the same name as the alias. For instance, the query
SELECT name FROM person AS author WHERE job = 'author';
Will return a data structure like this:
(set (author (person (name "Philip K Dick"))))
The underlying assumption is that aliasing is used for a purpose in the original query; for instance, to determine the context of the relation where it may be ambiguous.
SELECT * FROM person AS employee INNER JOIN person AS boss ON (employee.boss_id = boss.person_id)
Will generate a nested result structure similar to this -
(set (employee (person (person_id "...") (name "...") (salary "...") (boss (person (person_id "...") (name "...") (salary "..."))))))
If we neglected the alias, we would have 'person' directly nested under 'person', and the meaning would not be obvious. Note how the contents of the \s-1SQL\s0 query dynamically modifies the schema/structure of the result tree.
\s-1NOTE\s0 \s-1ON\s0 \s-1SQL\s0 \s-1SYNTAX\s0
Right now, DBStag is fussy about how you specify aliases; you must use \s-1AS\s0 - you must say
SELECT name FROM person AS author;
instead of
SELECT name FROM person author;
Nesting of relations
The main utility of querying using this module is in retrieving the nested relation elements from the flattened query results. Given a query over relations A, B, C, D,... there are a number of possible tree structures. Not all of the tree structures are meaningful or useful.
Usually it will make no sense to nest A under B if there is no foreign key relationship linking either A to B, or B to A. This is not always the case - it may be desirable to nest A under B if there is an intermediate linking table that is required at the relational level but not required in the tree structure.
DBStag will guess a structure/schema based on the ordering of the relations in your \s-1FROM\s0 clause. However, this guess can be over-ridden at either the \s-1SQL\s0 level (using DBStag specific \s-1SQL\s0 extensions) or at the \s-1API\s0 level.
The default algorithm is to nest each relation element under the relation element preceding it in the \s-1FROM\s0 clause; for instance:
SELECT * FROM a NATURAL JOIN b NATURAL JOIN c
If there are appropriately named foreign keys, the following data will be returned (assuming one column 'x_foo' in each of a, b and c)
(set (a (a_foo "...") (b (b_foo "...") (c (c_foo "...")))))
where 'x_foo' is a column in relation 'x'
This is not always desirable. If both b and c have foreign keys into table a, DBStag will not detect this - you have to guide it. There are two ways of doing this - you can guide by bracketing your \s-1FROM\s0 clause like this:
SELECT * FROM (a NATURAL JOIN b) NATURAL JOIN c
This will generate
(set (a (a_foo "...") (b (b_foo "...")) (c (c_foo "..."))))
Now b and c are siblings in the tree. The algorithm is similar to before: nest each relation element under the relation element preceding it; or, if the preceding item in the \s-1FROM\s0 clause is a bracketed structure, nest it under the first relational element in the bracketed structure.
(Note that in MySQL you may not place brackets in the \s-1FROM\s0 clause in this way)
Another way to achieve the same thing is to specify the desired tree structure using a DBStag specific \s-1SQL\s0 extension. The DBStag specific component is removed from the \s-1SQL\s0 before being presented to the \s-1DBMS\s0. The extension is the \s-1USE\s0 \s-1NESTING\s0 clause, which should come at the end of the \s-1SQL\s0 query (and is subsequently removed before processing by the \s-1DBMS\s0).
SELECT * FROM a NATURAL JOIN b NATURAL JOIN c USE NESTING (set (a (b)(c)));
This will generate the same tree as above (i.e. 'b' and 'c' are siblings). Notice how the nesting in the clause is the same as the nesting in the resulting tree structure.
Note that 'set' is not a table in the underlying relational schema - the result data tree requires a named top level node to group all the 'a' relations under. You can call this top level element whatever you like.
If you are using the DBStag \s-1API\s0 directly, you can pass in the nesting structure as an argument to the select call; for instance:
my $xmlstr = $dbh->selectall_xml(-sql=>q[SELECT * FROM a NATURAL JOIN b NATURAL JOIN c], -nesting=>'(set (a (b)(c)))');
or the equivalent -
my $xmlstr = $dbh->selectall_xml(q[SELECT * FROM a NATURAL JOIN b NATURAL JOIN c], '(set (a (b)(c)))');
If you like, you can also use \s-1XML\s0 here (only at the \s-1API\s0 level, not at the \s-1SQL\s0 level) -
my $seq = $dbh->selectall_xml(-sql=>q[SELECT * FROM a NATURAL JOIN b NATURAL JOIN c], -nesting=>q[ <set> <a> <b></b> <c></c> </a> </set> ]);
As you can see, this is a little more verbose than the S-Expression
Most command line scripts that use this module should allow pass-through via the '-nesting' switch.
Aliasing of functions and expressions
If you alias a function or an expression, DBStag needs to know where to put the resulting column; the column must be aliased.
This is inferred from the first named column in the function or expression; for example, the \s-1SQL\s0 below uses the minus function:
SELECT blah.*, foo.*, foo.x-foo.y AS z
The z element will be nested under the foo element
You can force different nesting using a double underscore:
SELECT blah.*, foo.*, foo.x - foo.y AS blah_\|_z
This will nest the z element under the blah element
If you would like to override this behaviour and use the alias as the element name, pass in the -aliaspolicy=>'a' arg to the \s-1API\s0 call. If you wish to use the table names without nesting, use -aliaspolicy=>'t'.
DBStag returns Data::Stag structures that are equivalent to a simplified subset of \s-1XML\s0 (and also a simplified subset of lisp S-Expressions).
These structures are examples of semi-structured data - a good reference is this book -
Data on the Web: From Relations to Semistructured Data and XML Serge Abiteboul, Dan Suciu, Peter Buneman Morgan Kaufmann; 1st edition (January 2000)
The schema for the resulting Stag structures can be seen to conform to a schema that is dynamically determined at query-time from the underlying relational schema and from the specification of the query itself.
If you need to generate a \s-1DTD\s0 you can ause the stag-autoschema.pl script, which is part of the Data::Stag distribution
The following methods are for using the DBStag \s-1API\s0 to query a database
Usage - $dbh = DBIx::DBStag->connect($DSN); Returns - L<DBIx::DBStag> Args - see the connect() method in L<DBI>
This will be the first method you call to initiate a DBStag object
The \s-1DSN\s0 may be a standard \s-1DBI\s0 \s-1DSN\s0, or it can be a DBStag alias
Usage - $stag = $dbh->selectall_stag($sql); $stag = $dbh->selectall_stag($sql, $nesting_clause); $stag = $dbh->selectall_stag(-template=>$template, -bind=>{%variable_bindinfs}); Returns - L<Data::Stag> Args - sql string, [nesting string], [bind hashref], [template DBIx::DBStag::SQLTemplate]
Executes a query and returns a Data::Stag structure
An optional nesting expression can be passed in to control how the relation is decomposed into a tree. The nesting expression can be \s-1XML\s0 or an S-Expression; see above for details
Usage - $xml = $dbh->selectall_xml($sql); Returns - string Args - See selectall_stag()
As selectall_stag(), but the results are transformed into an \s-1XML\s0 string
Usage - $sxpr = $dbh->selectall_sxpr($sql); Returns - string Args - See selectall_stag()
As selectall_stag(), but the results are transformed into an S-Expression string; see Data::Stag for more details.
Usage - $dbh->selectall_sax(-sql=>$sql, -handler=>$sax_handler); Returns - string Args - sql string, [nesting string], handler SAX
As selectall_stag(), but the results are transformed into \s-1SAX\s0 events
[currently this is just a wrapper to selectall_xml but a genuine event generation model will later be used]
Usage - $tbl = $dbh->selectall_rows($sql); Returns - arrayref of arrayref Args - See selectall_stag()
As selectall_stag(), but the results of the \s-1SQL\s0 query are left undecomposed and unnested. The resulting structure is just a flat table; the first row is the column headings. This is similar to \s-1DBI-\s0>selectall_arrayref(). The main reason to use this over the direct \s-1DBI\s0 method is to take advantage of other stag functionality, such as templates
Usage - $prepare_h = $dbh->prepare_stag(-template=>$template); Returns - hashref (see below) Args - See selectall_stag()
Returns a hashref
{ sth=>$sth, exec_args=>\@exec_args, cols=>\@cols, col_aliases_ordered=>\@col_aliases_ordered, alias=>$aliasstruct, nesting=>$nesting };
The following methods are for using the DBStag \s-1API\s0 to store nested data in a database
Usage - $dbh->storenode($stag); Returns - Args - L<Data::Stag>
\s-1SEE\s0 \s-1ALSO:\s0 The stag-storenode.pl script
Recursively stores a stag tree structure in the database.
The database schema is introspected for most of the mapping data, but you can supply your own (see later)
The Stag tree/XML must be a direct mapping of the relational schema. Column and table names must correspond to element names. Elements may be nested. Different styles of XML-Relational mapping may be used: XORT-style and the more compact Stag-style
XORT-style mapping
With a XORT-style mapping, elements corresponding to tables can be nested under elements corresponding to foreign keys.
For example, if the relational schema has a foreign key from table person to table address, the following \s-1XML\s0 is permissable:
<person> <name>..</name> <address_id> <address> </address> </address_id> </person>
The address node will be stored in the database and collapsed to whatever the value of the primary key is.
Stag-style mapping
Stag-style is more compact, but sometimes relies on the presence of a dbstag_metadata element to specify how foreign keys are mapped
Operations
Operations are specified as attributes inside elements, specifying whether the nod should be inserted, updated, looked up or stored/forced. Operations are optional (default is force/store).
<person op="insert"> <name>fred</name> <address_id op="lookup"> <streetaddr>..</> <city>..</> </address_id> </person>
The above will always insert into the person table (which may be quite dangerous; if an entry with the same unique constraint exists, an error will be thrown). Assuming (streetaddr,city) is a unique constraint for the address table, this will lookup the specified address (and not modify the table) and use the returned pk value for the person.address_id foreign key
The operations are:
looks up (by unique constraints) first; if exists, will do an update. if does not exist, will do an insert
insert only. \s-1DBMS\s0 will throw error if row with same \s-1UC\s0 exists
update only. \s-1DBMS\s0 will throw error if a row the with the specified \s-1UC\s0 cannot be found
finds the pk value using one of the unique constraints present in the \s-1XML\s0 node
deletes row that has matching \s-1UC\s0
Operations can be used in either \s-1XORT\s0 or Stag mode
Macros
Macros can be used with either \s-1XORT\s0 or Stag style mappings. Macros allow you to refer to the same node later on in the \s-1XML\s0
<person op="lookup" id="joe"> <name>joe</name> </person> <person op="lookup" id="fred"> <name>fred</name> </person> ... <person_relationship> <type>friend</type> <person1_id>joe</person1_id> <person2_id>fred</person2_id> </person_relationship>
Assuming name is a unique constraint for person, and person_relationship has two foreign keys named person1_id and person2_id linking to the person table, DBStag will first lookup the two person rows by name (throwing an error if not present) and use the returned pk values to populate the person_relationship table
How it works
Before a node is stored, certain subnodes will be pre-stored; these are subnodes for which there is a foreign key mapping \s-1FROM\s0 the parent node \s-1TO\s0 the child node. This pre-storage is recursive.
After these nodes are stored, the current node is either INSERTed or UPDATEd. The database is introspected for \s-1UNIQUE\s0 constraints; these are used as keys. If there exists a row in the database with matching key, then the node is UPDATEd; otherwise it is INSERTed.
(primary keys from pre-stored nodes become foreign key values in the existing node)
Subsequently, all subnodes that were not pre-stored are now post-stored. The primary key for the existing node will become foreign keys for the post-stored subnodes.
Usage - $dbh->force_safe_node_names(1); Returns - bool Args - bool [optional]
If this is set, then before storage, all node names are made DB-safe; they are lowercased, and the following transform is applied:
tr/a-z0-9_//cd;
Usage - $dbh->mapping(["alias/table.col=fktable.fkcol"]); Returns - Args - array
Creates a stag-relational mapping (for storing data only)
Occasionally not enough information can be obtained from db introspection; you can provide extra mapping data this way.
Occasionally you stag objects/data/XML will contain aliases that do not correspond to actual \s-1SQL\s0 relations; the aliases are intermediate nodes that provide information on which foreign key column to use
For example, with data like this:
(person (name "...") (favourite_film (film (....)) (least_favourite_film (film (....)))))
There may only be two \s-1SQL\s0 tables: person and film; person would have two foreign key columns into film. The mapping may look like this
["favourite_film/person.favourite_film_id=film.film_id", "least_favourite_film/person.least_favourite_film_id=film.film_id"]
The mapping can also be supplied in the xml that is loaded; any node named \*(L"dbstag_metadata\*(R" will not be loaded; it is used to supply the mapping. For example:
<personset> <dbstag_mapping> <map>favourite_film/person.favourite_film_id=film.film_id</map> <map>least_favourite_film/person.least_favourite_film_id=film.film_id</map> </dbstag_mapping> <person>...
Usage - $dbh->mapconf("mydb-stagmap.stm"); Returns - Args - filename
sets the conf file containing the stag-relational mappings
This is not of any use for a XORT-style mapping, where foreign key columns are explicitly stated
See mapping() above
The file contains line like:
favourite_film/person.favourite_film_id=film.film_id least_favourite_film/person.least_favourite_film_id=film.film_id
Usage - $dbh->noupdate_h({person=>1}) Returns - Args - hashref
Keys of hash are names of nodes that do not get updated - if a unique key is queried for and does not exist, the node will be inserted and subnodes will be stored; if the unique key does exist in the db, then this will not be updated; subnodes will not be stored
Usage - $dbh->trust_primary_key_values(1) Returns - bool Args - bool (optional)
The default behaviour of the storenode() method is to remap all surrogate \s-1PRIMARY\s0 \s-1KEY\s0 values it comes across.
A surrogate primary key is typically a primary key of type \s-1SERIAL\s0 (or \s-1AUTO_INCREMENT\s0) in MySQL. They are identifiers assigned automatically be the database with no semantics.
It may be desirable to store the same data in two different databases. We would generally not expect the surrogate IDs to match between databases, even if the rest of the data does.
(If you do not use surrogate primary key columns in your load xml, then you can ignore this accessor)
You should \s-1NOT\s0 use this method in conjunction with Macros
If you use primary key columns in your \s-1XML\s0, and the primary keys are not surrogate, then youshould set this. If this accessor is set to non-zero (true) then the primary key values in the \s-1XML\s0 will be used.
If your db has surrogate/auto-increment/serial PKs, and you wish to use these \s-1PK\s0 columns in your \s-1XML\s0, yet you want to make \s-1XML\s0 that can be exported from one db and imported into another, then the default behaviour will be fine.
For example, if we extract a 'person' from a db with surrogate \s-1PK\s0 id and unique key ssno, we may get this:
<person> <id>23</id> <name>fred</name> <ssno>1234-567</ssno> </person>
If we then import this into an entirely fresh db, with no rows in table person, then the default behaviour of storenode() will create a row like this:
<person> <id>1</id> <name>fred</name> <ssno>1234-567</ssno> </person>
The \s-1PK\s0 val 23 has been mapped to 1 (all foreign keys that point to person.id=23 will now point to person.id=1)
If we were to first call $sdbh->trust_primary_key_values\|(1), then person.id would remain to be 23. This would only be appropriate behaviour if we were storing back into the same db we retrieved from.
Usage - $dbh->tracenode('person/name')
Traces on \s-1STDERR\s0 inserts/updates on a particular element type (table), displaying the sub-element (column value).
Usage - $dbh->is_caching_on('person', 1) Returns - number Args - number 0: off (default) 1: memory-caching ON 2: memory-caching OFF, bulkload ON 3: memory-caching ON, bulkload ON
IN-MEMORY \s-1CACHING\s0
By default no in-memory caching is used. If this is set to 1, then an in-memory cache is used for any particular element. No cache management is used, so you should be sure not to cache elements that will cause memory overloads.
Setting this will not affect the final result, it is purely an efficiency measure for use with storenode().
The cache is indexed by all unique keys for that particular element/table, wherever those unique keys are set
\s-1BULKLOAD\s0
If bulkload is used without memory-caching (set to 2), then only INSERTs will be performed for this element. Note that this could potentially cause a unique key violation, if the same element is present twice
If bulkload is used with memory-caching (set to 3) then only INSERTs will be performed; the unique serial/autoincrement identifiers for those inserts will be cached and used. This means you can have the same element twice. However, the load must take place in one session, otherwise the contents of memory will be lost
Usage - $dbh->clear_cache; Returns - Args - none
Clears the in-memory cache
Caches are not automatically managed - the \s-1API\s0 user is responsible for making suring the cache does not get too big
Usage - print $dbh->cache_summary->xml Returns - L<Data::Stag> Args -
Gives a summary of the size of the in-memory cache by keys. This can be used for automatic cache management:
$person_cache = $dbh->cache_summary->get_person; my @index_nodes = $person_cache->tnodes; foreach (@index_nodes) { if ($_->data > MAX_PERSON_CACHE_SIZE) { $dbh->clear_cache; } }
DBStag comes with its own \s-1SQL\s0 templating system. This allows you to reuse the same canned \s-1SQL\s0 or similar \s-1SQL\s0 qeuries in different contexts. See DBIx::DBStag::SQLTemplate
Usage - $template = $dbh->find_template("my-template-name"); Returns - L<DBIx::DBStag::SQLTemplate> Args - str
Returns an object representing a canned paramterized \s-1SQL\s0 query. See DBIx::DBStag::SQLTemplate for documentation on templates
Usage - $templates = $dbh->list_templates(); Returns - Arrayref of L<DBIx::DBStag::SQLTemplate> Args -
Returns a list of \s-1ALL\s0 defined templates - See DBIx::DBStag::SQLTemplate
Usage - $templates = $dbh->find_templates_by_schema($schema_name); Returns - Arrayref of L<DBIx::DBStag::SQLTemplate> Args - str
Returns a list of templates for a particular schema - See DBIx::DBStag::SQLTemplate
Usage - $templates = $dbh->find_templates_by_dbname("mydb"); Returns - Arrayref of L<DBIx::DBStag::SQLTemplate> Args - db name
Returns a list of templates for a particular db
Requires resources to be set up (see below)
Generally when connecting to a database, it is necessary to specify a \s-1DBI\s0 style \s-1DSN\s0 locator. DBStag also allows you specify a resource list file which maps logical names to full locators
The following methods allows you to use a resource list
Usage - $rlist = $dbh->resources_list Returns - arrayref to a hashref Args - none
Returns a list of resources; each resource is a hash
{name=>"mydbname", type=>"rdb", schema=>"myschema", }
The above methods rely on you having a file describing all the relational dbs available to you, and setting the env var \s-1DBSTAG_DBIMAP_FILE\s0 set (this is a : separated list of paths).
This is alpha code - not fully documented, \s-1API\s0 may change
Currently a resources file is a whitespace delimited text file - XML/Sxpr/IText definitions may be available later
Here is an example of a resources file:
# LOCAL mytestdb rdb Pg:mytestdb schema=test
# SYSTEM worldfactbook rdb Pg:[email protected] schema=wfb employees rdb Pg:[email protected] schema=employees
The first column is the nickname or logical name of the resource/db. This nickname can be used instead of the full \s-1DBI\s0 locator path (eg you can just use employees instead of dbi:Pg:dbname=employees;host=db2.mycompany.com
The second column is the resource type - rdb is for relational database. You can use the same file to track other system datasources available to you, but DBStag is only interested in relational dbs.
The 3rd column is a way of locating the resource - driver:name@host
The 4th column is a ; separated list of tag=value pairs; the most important tag is the schema tag. Multiple dbs may share the same schema, and hence share \s-1SQL\s0 Templates
DBStag is usable without writing any perl, you can use command line scripts and files that utilise tree structures (\s-1XML\s0, S-Expressions)
selectall_xml.pl -d <DSN> [-n <nestexpr>] <SQL> Queries database and writes decomposed relation as \s-1XML\s0 Can also be used with templates: selectall_xml.pl -d <DSN> /<templatename> <var1> <var2> ... <varN>
selectall_html.pl -d <DSN> [-n <nestexpr>] <SQL> Queries database and writes decomposed relation as \s-1HTML\s0 with nested tables indicating the nested structures.
stag-storenode.pl -d <DSN> <file> Stores data from a file (Supported formats: \s-1XML\s0, Sxpr, IText - see Data::Stag) in a normalized database. Gets it right most of the time. \s-1TODO\s0 - metadata help
stag-autoddl.pl [-l <linktable>]* <file> Takes data from a file (Supported formats: \s-1XML\s0, Sxpr, IText - see Data::Stag) and generates a relational schema in the form of \s-1SQL\s0 \s-1CREATE\s0 \s-1TABLE\s0 statements.
setting this environment will cause all \s-1SQL\s0 statements to be printed on \s-1STDERR\s0, as well as a full trace of how nodes are stored
The \s-1SQL\s0 parsing can be quite particular - sometimes the \s-1SQL\s0 can be parsed by the \s-1DBMS\s0 but not by DBStag. The error messages are not always helpful.
There are probably a few cases the \s-1SQL\s0 \s-1SELECT\s0 parsing grammar cannot deal with.
If you want to select from views, you need to hack DBIx::DBSchema (as of v0.21)
Use SQL::Translator to make \s-1SQL\s0 \s-1DDL\s0 generation less Pg-specific; also for deducing foreign keys (right now foreign keys are guessed by the name of the column, eg table_id)
Can we cache the grammar so that startup is not so slow?
Improve algorithm so that events are fired rather than building up entire structure in-memory
Tie in all \s-1DBI\s0 attributes accessible by hash, i.e.: $dbh->{...}
Error handling
<http://stag.sourceforge.net>
Chris Mungall <cjm \s-1AT\s0 fruitfly \s-1DOT\s0 org>
Copyright (c) 2004 Chris Mungall
This module is free software. You may distribute this module under the same terms as perl itself