medic 1.1.0

A command line tool to manage a PubMed DB mirror.

The Swiss Army knife to parse MEDLINE XML files or download eUtils’ PubMed XML records, bootstrapping a MEDLINE/PubMed database, updating and/or deleting the records, and writing the contents of selected PMIDs into flat-files.

Synopsis

medic [options] CMD FILE|PMID...

medic parse baseline/medline*.xml.gz
medic --update parse update/medline*.xml.gz
medic --pmid-lists delete delete.txt
medic --url sqlite://tmp.db insert pubmed.xml
medic --pmid-lists update changed_pmids.txt
medic --all update pubmed.xml
medic --format html --output /var/www/medline.html write 2874014 1028734 1298474

Setup

If you are not using pip install medic, install all dependencies/requirements:

pip install sqlalchemy
# only if using python3 < 3.2:
pip install argparse

Install the DB driver you prefer to use (supported are PostgreSQL and SQLite):

pip install psycopg2

Create the PostreSQL database:

createdb medline

If you are fine working with SQLite, you only need to use the path to the SQLite DB file in the URL option:

medic insert --url sqlite:///tmp.db 123456

Description

medic [options] COMMAND PMID|FILE...

The --url URL option represents the DSN of the database and might be needed (default: postgresql://localhost/medline); For example:

PostgreSQL

postgresql://host//dbname

SQLite DB

sqlite:////absolute/path/to/foo.db or sqlite:///relative/path/to/foo.db

The five COMMAND arguments:

insert

Create records in the DB by parsing MEDLINE XML files or by downloading PubMed XML from NCBI eUtils for a list of PMIDs.

write

Write records as plaintext files to a directory, each file named as “<pmid>.txt”, and containing most of the DB stored content or just the TIAB (title and abstract). In addition, a single file in TSV or HTML format can be generated (see option --format).

update

Insert or update records in the DB (instead of creating them); note that if a record exists, but is added with create, this would throw an IntegrityError. If you are not sure if the records are in the DB or not, use update (N.B. that update is slower).

delete

Delete records from the DB for a list of PMIDs (use --pmid-lists!)

parse

Does not interact with the DB, but rather creates “.tab” files for each table that later can be used to load a database, particularly useful when bootstrapping a large collection.

For example, to download two PubMed records by PMID and update them in the DB:

medic update 100000 123456

Add a single MEDLINE or PubMed XML file to the database:

medic insert pudmed.xml

Export a few records from the database as HTML (to STDOUT):

medic write --format html 292837491 128374 213487

Note that if the suffix “.gz” is present, the parser automatically decompresses the XML file(s) first. This feature only works with GNU-zipped files and the “.gz” suffix must be present.

Therefore, command line arguments are treated as follows:

integer values

are always treated as PMIDs to download PubMed XML data

all other values

are always treated as MEDLINE XML files to parse unless you use the option --pmid-lists

files ending in “.gz”

are always treated as gzipped MEDLINE XML files

Requirements

• Python 3.2+

• SQL Alchewy 0.8+

• PostgreSQL 8.4+ or SQLite 3.7+

Note that while any SQL Alchemy DB might work, it is strongly discouraged to use any other combination that PostgeSQL and psycogp2 or SQLite and the Python STDLIB drivers, because it has not been tested.

Loading MEDLINE

Please be aware that the MEDLINE distribution is not unique, meaning that it contains a few records multiple times (see the section about Version IDs).

Parsing and loading the baseline into a PostgreSQL DB on the same machine:

medic parse baseline/medline14n*.xml.gz

for table in records descriptors qualifiers authors \
sections databases identifiers chemicals;
  do psql medline -c "COPY $table FROM '`pwd`/${table}.tab';";
done

For the update files, you need to go one-by-one, adding each one in order, and using the flag --update when parsing the XML. After parsing an XML file and before loading the dump, run medic delete --pmid-lists delete.txt to get rid of all entities that will be updated or should be removed (PMIDs listed as DeleteCitations):

# parse a MEDLINE update file:
medic --update parse medline14n1234.xml.gz

# delete updated and DeleteCitation records:
medic --pmid-lists delete delete.txt

# load all tables; see below, loading baseline:
for table in records descriptors qualifiers authors \
sections databases identifiers chemicals;
  do psql medline -c "COPY $table FROM '`pwd`/${table}.tab';";
done

Version IDs

MEDLINE has began to use versions to allow publishers to add multiple citations for the same PMID. This only occurs with 71 articles from one journal, “PLOS Curr”, in the 2013 baseline, creating a total of 149 non-unique records.

As this is the only journal and as there should only be one abstract per publication in the database, alternative versions are currently being ignored. In other words, if a MedlineCitation has a VersionID value, that records can be skipped to avoid DB errors from non-unique records.

For example, in the 2013 baseline, PMID 20029614 is present ten times in the baseline, each version at a different stage of revision. Because it is the first entry (in the order they appear in the baseline files) without a VersionID or a version of “1” that so far is the relevant record, medic by default filters citations with other versions than “1”. If you do want to process other versions of a citation, use the option --all.

In short, this tool by default removes alternate citations.

Database ER Model

[Author] → [Medline] ← [Descriptor] ← [Qualifier]
            ↑     ↑
  [Identifier]   [Section]  [Database]  [Chemical]

Medline (records)

pmid:BIGINT, status:ENUM(state), journal:VARCHAR(256), created:DATE, completed:DATE, revised:DATE, modified:DATE

Author (authors)

pmid:FK(Medline), pos:SMALLINT, name:TEXT, initials:VARCHAR(128), forename:VARCHAR(128), suffix:VARCHAR(128),

Descriptor (descriptors)

pmid:FK(Medline), pos:SMALLINT, name:TEXT, major:BOOL

Qualifier (qualifiers)

pmid:FK(Descriptor), pos:FK(Descriptor), sub:SMALLINT, name:TEXT, major:BOOL

Identifier (identifiers)

pmid:FK(Medline), namespace:VARCHAR(32), value:VARCHAR(256)

Database (databases)

pmid:FK(Medline), name:VARCHAR(32), accession:VARCHAR(256)

Chemical (chemicals)

pmid:FK(Medline), num:VARCHAR(32), uid:VARCHAR(256), name:VARCHAR(256)

Section (sections)

pmid:FK(Medline), seq:SMALLINT, name:ENUM(section), label:VARCHAR(256), content:TEXT

• bold (Composite) Primary Key

• italic NOT NULL (Strings that may not be NULL are also never empty.)

Supported XML Elements

Entities

• The citation (Medline and Identifier)

• Title, Abstract, and Copyright (Section)

• Author (Author)

• Chemical (Chemcial)

• DataBank (Database)

• MeshHeading (Descriptor and Qualifier)

• DeleteCitation (for deleting records when parsing updates)

Fields/Values

• AbstractText (Section.name “Abstract” or the NlmCategory, Section.content with Label as Section.label)

• AccessionNumber (Database.accession)

• ArticleId (Identifier.value with IdType as Identifier.namesapce; only available in online PubMed XML)

• ArticleTitle (Section.name “Title”, Section.content)

• CollectiveName (Author.name)

• CopyrightInformation (Section.name “Copyright”, Section.content)

• DataBankName (Database.name)

• DateCompleted (Medline.completed)

• DateCreated (Medline.created)

• DateRevised (Medline.revised)

• DescriptorName (Descriptor.name with MajorTopicYN as Descriptor.major)

• ELocationID (Identifier.value with EIdType as Identifier.namespace)

• ForeName (Author.forename)

• Initials (Author.initials)

• LastName (Author.name)

• MedlineCitation (only Status as Medline.status)

• MedlineTA (Medline.journal)

• NameOfSubstance (Chemcial.name)

• OtherID (Identifier.value iff Source is “PMC” with Identifier.namespace as “pmc”)

• PMID (Medline.pmid)

• QualifierName (Qualifier.name with MajorTopicYN as Qualifier.major)

• RegistryNumber (Chemical.uid)

• Suffix (Author.suffix)

• VernacularTitle (Section.name “Vernacular”, Section.content)

Version History

1.1.0

• --update parse now writes a file to use with --pmid-lists delete

• fixed a bug with CRUD manager

• added a man page

1.0.2

• fixes to make the PyPi version and pip install medic work

1.0.1

• updates to the setup.py and README.rst files

1.0.0

• initial release

Copyright and License

License: GNU GPL v3. Copryright 2012, 2013 Florian Leitner. All rights reserved.