Using DQMan or Document Admistrator, what's DQL statement to get hash of document in DCTM?
Select ... ?
If it's not possible how can I get it?
(I know exactly which is the document, r_chronicle_id, r_object_id, etc...)
AFAIK there is no field representing a document hash, but take a look in the dmr_content object table. It should be here if there is one (I haven't checked I several years).
Alternatively you would have to get it with API - either there is a method or you should do it yourself. Take a look in the api guide.
Edit: just searched the object reference guide. Turns out that there is a field in dmr_content. It's called r_content_hash.
Have a look at it to see if your docbase fulfills requirements to have this field populated. Maybe you're in luck ;-)
Related
I would like to know if it is possible to do a search like this:
"give me all objects where description has more than 1 value"
The short answer is no. At least not from a single LDAP Query without somehow parsing the results.
I know of a tool that will provide those results however it has not been updated in a while but last time I used it, it worked.
I am pretty new to LUCENE search engine, want to know the functionality of OpenMode.CREATE_OR_APPEND, deleteDocuments? Also, indexSearcher.search method can accept either Term or Query as a parameter, to fetch documents. Can you help me out in which scenario I need to use term and query?
The OpenMode does not affect the behavior of deleteDocuments. It only affects what happens when you open the Indexwriter:
CREATE - Creates a new index. If one already exists, it will be overwritten.
CREATE_OR_APPEND - Uses an existing index, or creates it if none currently exists.
APPEND - Uses an existing index. If none currently exists, throws an IOException.
I'm not aware of any IndexSearcher.search method that takes a Term as an argument. If you can link to what you are referring to, that might be helpful.
However, if you want to search for a term, you can just use TermQuery.
Is there a way to get Lucene/Elasticsearch to just show what fields have been indexed in a given index? I'm trying to figure out whether certain fields have been indexed properly as a result of configuration options, but I have no idea how to make that determination.
You can check the mappings for a specific index and type via a call to:
http://localhost:9200/index/type/_mapping
Anything indexed should have an entry there.
See also analyze API to see how text is broken into terms.
http://www.elasticsearch.org/guide/reference/api/admin-indices-analyze.html
I'm running a simple test--trying to index something and then search for it. I index a simple document, but then when a search for a string in it, I get back what looks to be an empty document (it has no fields). Lucene seems to be doing something, because if I search for a word that's not in the document, it returns 0 results.
Any reason why Lucene would reliably return a document when it finds one that matches the given query, and yet that document has nothing in it?
More details:
I'm actually running Lucandra (Lucene + Cassandra). That certainly may be a relevant detail, but not sure.
The fields are set to Field.Store/YES and Field.Index/ANALYZED
Interestingly, I'm able to get this to work just fine on my local machine, but when we put it on our main server (which is a multi-node cassandra setup), I get the behavior described above. So this seems like probably the relevant detail, but unfortunately, I see no error message to clue me in to what specifically is causing it.
Unsure if this will work with Lucandra, but you have tried opening the index using Luke? Viewing the index contents with Luke might help
It's hard to tell what the problem is since you only provide a very abstract description. However, it sounds a bit like you are not storing the field value in the index. There are different modes for indexing a field. One option determines whether the original value is stored in the index to retrieve it later:
http://lucene.apache.org/java/3_0_0/api/core/org/apache/lucene/document/Field.Store.html
See also the description of the enclosing class Field
Read: http://anismiles.wordpress.com/2010/05/27/lucandra-an-inside-story/
I read that Lucene has an internal query language where one specifies : and you make combinations of these using boolean operators.
I read all about it on their website and it works just fine in LUKE, I can do things like
field1:value1 AND field2:value2
and it will return seemingly correct results.
My problem is how do I pass this who Lucene query into the API? I've seen QueryParser, but I have to specifiy a field. Does this mean I still have to manually parse my input string, fields, values, parenthesis, etc or is there a way to feed the whole thing in and let lucene do it's thing?
I'm using Lucene.NET but since it's a method by method port of the orignal java, any advice is appreciated.
Are you asking whether you need to force your user to enter the field? If so, the query parser has a default field. Here's a little more info. As long as you have a default field that will do the job, they don't need to specify fields.
If you're asking how to get a Query object from the String, you need the parse method. It understands about fields, and the default field, etc. mentioned earlier. You just need to make sure that the query parser and the index builder are both using the same analysis.