stag-db(1) persistent storage and retrieval for stag data (xml, sxpr, itext)

SYNOPSIS


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

DESCRIPTION

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

ARGUMENTS

-i INDEXFILE

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

-r RELATION-NAME

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 

  <person_set>
    <person>
      <id>...</id>
    </person>
    <person>
      <id>...</id>
    </person>
    ...
  </person_set>

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

-k UNIQUE-KEY

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

-u UNIQUE-KEY

Synonym for -k

-p PARSER

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

-q QUERY-ID

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

-top NODE-NAME

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)

-qf QUERY-FILE

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

-keys

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

-w WRITER

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)

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