Catmandu::Fix::lookup_in_store(3pm)

NAME

Catmandu::Fix::lookup_in_store - change the value of a HASH key or ARRAY index by looking up its value in a store

SYNOPSIS

   # Lookup in an SQLLite database
   lookup_in_store(foo.bar, DBI, data_source: "dbi:SQLite:path/data.sqlite")
   # Lookup in a MongoDB database
   lookup_in_store(foo.bar, MongoDB, database_name: lookups, bag: mydata)
   # Lookup in a MongoDB database, using the default bag and a default value when nothing found
   lookup_in_store(foo.bar, MongoDB, database_name: lookups, default: 'default value')
   # Lookup in a MongoDB database, using the default bag and delete the foo.bar field when nothing found
   lookup_in_store(foo.bar, MongoDB, database_name: lookups, delete: 1)
   # Or, a much faster option: use a named store in a catmandu.yml file
   #
   # store:
   #  mydbi:
   #    package: DBI
   #    options:
   #      data_source: "dbi:SQLite:path/data.sqlite"
   #  mymongo:
   #    package: MongoDB
   #    options:
   #      database_name: lookups
   lookup_in_store(foo.bar, mydbi)
   lookup_in_store(foo.bar, mymongo, bag: mydata)
   lookup_in_store(foo.bar, mymongo, default: 'default value')
   lookup_in_store(foo.bar, mymongo, delete: 1)

DESCRIPTION

lookup_in_store(PATH,STORE[,store_param: store_val, ...][,bag: bag_name][,delete:1][,default:value])

Use the lookup_in_store fix to match a field in a record to the "_id" field in a Catmandu::Store of choice. For instance, if a Catmandu::Store contains these records:

    ---
    _id: water
    fr: l'eau
    de: wasser
    en: water
    nl: water
    ---
    _id: tree
    fr: arbre
    de: baum
    en: tree
    nl: boom

And you data contains these fields:

    ---
    _id: 001
    tag: tree
    ---
    _id: 002
    tag: water

Then, the fix below will lookup a tag in the Catmandu::Store and replace it with the database value:

    lookup_in_store(tag, DBI, data_source: "dbi:SQLite:path/data.sqlite")

The resulting data will contain:

    ---
    _id: 001
    tag:
      _id: tree
      fr: arbre
      de: baum
      en: tree
      nl: boom
    ---
    _id: 002
    tag:
      _id: water
      fr: l'eau
      de: wasser
      en: water
      nl: water

DATABASE CONNECTIONS

For every call to a "lookup_in_store" a new database connection is created. It is much more effient to used named stores in a "catmandu.yml" file. This file needs to contain all the connection parameters to the database. E.g.

    store:
       mystore:
         package: MongoDB
         options:
            database_name: mydata

The "catmandu.yml" file should be available in the same directory as where the "catmandu" command is executed. Or, this directory can be set with the "-L" option:

    $ catmandu -L /tmp/path convert ...