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persistent storage and retrieval for stag data (xml, sxpr, itext)


  stag-db -r person -k social_security_no -i ./person-idx myrecords.xml
  stag-db -i ./person-idx -q 999-9999-9999 -q 888-8888-8888


Builds a simple file-based database for persistent storage and retrieval of nodes from a stag compatible document.

Imagine you have a very large file of data, in a stag compatible format such as XML. You want to index all the elements of type person; each person can be uniquely identified by social_security_no, which is a direct subnode of person

The first thing to do is to build an index file, which will be stored in your current directory:

  stag-db -r person -k social_security_no -i ./person-idx myrecords.xml

You can then use the index "person-idx" to retrieve person nodes by their social security number

  stag-db -i ./person-idx -q 999-9999-9999 > some-person.xml

You can export using different stag formats

  stag-db -i ./person-idx -q 999-9999-9999 -w sxpr > some-person.xml

You can retrieve multiple nodes (although these need to be rooted to make a valid file)

  stag-db -i ./person-idx -q 999-9999-9999 -q 888-8888-8888 -top personset

Or you can use a list of IDs from a file (newline delimited)

  stag-db -i ./person-idx -qf my_ss_nmbrs.txt -top personset



This file will be used as the persistent index for storage/retrieval


This is the name of the stag node (XML element) that will be stored in the index; for example, with the XML below you may want to use the node name person and the unique key id


This flag should only be used when you want to store data


This node will be used as the unique/primary key for the data

This node should be nested directly below the node that is being stored in the index - if it is more that one below, specify a path

This flag should only be used when you want to store data


Synonym for -k


This can be the name of a stag supported format (xml, sxpr, itext) - XML is assumed by default

It can also be a module name - this module is used to parse the input file into a stag stream; see Data::Stag::BaseGenerator for details on writing your own parsers/event generators

This flag should only be used when you want to store data


Fetches the relation/node with unique key value equal to query-id

Multiple arguments can be passed by specifying -q multple times

This flag should only be used when you want to query data


If this is specified in conjunction with -q or -qf then all the query result nodes will be nested inside a node with this name (ie this provides a root for the resulting document tree)


This is a file of newline-seperated IDs; this is useful for querying the index in batch


This will write a list of all primary keys in the index


This format will be used to write the data; can be any stag format (xml, sxpr, itext) - default XML.

Can also be a module that catches the incoming stag event stream and does something with it (for example, this could be a module you write yourself that transforms the stag events into HTML)

See Also


For more complex stag to database mapping, see DBIx::DBStag and the scripts




2024-01-25 perl v5.38.2 User Contributed Perl Documentation