SRU enables you to conduct purposeful research without having your own database.
OAI facilitates the constant synchronisation of large data sets; for this, a current set of basic data stock must be imported into your own database.
The SRU website of the Library of Congress provides a corresponding overview of software for use with SRU.
Address or name of data source: e.g. https://services.dnb.de/sru or DNB-catalogue (in most cases you are free to choose the designation in this field)
Server name/host name/computer: services.dnb.de
Port: 443 (HTTPS-Protokoll)
Data base designation/path: sru/dnb or sru/zdb or sru/authorities etc.
Format/syntax: MARC 21/USMARC
Coding: UTF-8 (decomposed)
The SRU interface delivers an error diagnosis in XML (diagnostic) depending on the standard.
Example:
<diagnostics>
<diag:diagnostic xmlns:diag="http://www.loc.gov/zing/srw/diagnostic/">
<diag:uri>info:srw/diagnostic/1/8</diag:uri>
<diag:details>Unsupported parameter</diag:details>
<diag:message>[quer]</diag:message>
</diag:diagnostic>
</diagnostics>
If no index is entered in the SRU request, the request is forwarded to the most extensive index in the catalogue selected (fallback).
In an SRU request, these have to be converted into URL code (UTF-8 hexadecimal, also known as percent encoding). Examples: the letter ä is converted to %C3%A4, a space to %20 and a slash to %2F. Search terms can be enclosed in quotation marks (“search term”). If a search term contains the signs < > = / ( ) or spaces, these must be enclosed by quotation marks (for example the library code "1w/r" in URL code: "1w%2Fr") (see Standard).
Markup characters (<, > and &) in an SRU response are transported in a CDATA section.
The SRU interface responds with “number of records 0”.
If you are just getting started with processing metadata, useful programmes include the software suite Catmandu, OpenRefine or Metafacture, while data can be analysed with "Konstanz Information Miner" (KNIME) or the Metadata Quality Assurance Framework. The metadata.community offers an overview of current tools and softwares. A more detailed overview is provided in the presentation slides "Open Source Software zur Verarbeitung und Analyse von Metadaten" (available only in German) and the article "Survey of Tools for Linked Data Consumption".
For depositors of online publications, the metadata of the objects submitted to DNB are available via the SRU interface. To do so, you require the IDO (DNB identifier for a depositor of online publications) assigned by DNB. It is equivalent to the username/login when delivering via the hotfolder (SFTP). If you don't know your IDO, please contact us at np-info@dnb.de.
Please note the limitation of 99,000 records in the search results per SRU query. If needed, a limitation to a specified year of publication can be helpful in order to reduce your search results to under 99,000 data records.
Example IDO:
https://services.dnb.de/sru/dnb?version=1.1&operation=searchRetrieve&query=ido%3D%2236208644%22&recordSchema=MARC21-xml
Example IDO with limitation to year of publication:
https://services.dnb.de/sru/dnb?version=1.1&operation=searchRetrieve&query=ido%3D%2236208644%22%20and%20jhr%3D%222024%22&recordSchema=MARC21-xml
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