I am using solr and looked over the documentations but couldn't find a way to get a single record from Solr by using a key?
If I know the key value of the record what is the query I need to pass to Solr to obtain this record?
Thanks.
Not sure what you mean by key, but guessing from context, you mean a field defined by your schema, if this is the case, you could issue the following:
// Assumes Id is a schema field
// If via solr admin
q=Id:1
// Properly escaped
q=Id%3A1
Related
i am pretty new to solr. and i don't know what is the best practice for the id column.
currently i wish to exclude the internal "id" parameter from solr search results (i am using my custom user_id field ).
i know i can use the fl=field1,field2. but this means specifying all my fields here. and i don't have a deep knowledge in solr and i fear this will hurt performance. ?
another question is it recommended to add another field user_id or overwrite the default id field ?
thank you very much.
If the value you have in your user_id field is unique, index that into your id column or define the user_id field as your unique key instead and don't use the id field.
The important thing is that there's a unique field in your document so that Solr knows when a document should be updated compared to when a new document should be added instead.
If the id field is not relevant / secret, I'm not sure why you'd be worried about including it.
Let's say you have a simple forms automation application, and you want to index every submitted form in a Solr collection. Let's also say that form content is open-ended so that the user can create custom fields on the form and so forth.
Since users can define custom forms, you can't really predefine fields to Solr, so we've been using Solr's "schema-less" or managed schema mode. It works well, except for one problem.
Let's say a form comes through with a field called "ID" and a value of "9". If this is the first time Solr has seen a field called "ID", it dutifully updates it's schema, and since the value of this field is numeric, Solr assigns it a data type of one of it's numeric data types (we see "plong" a lot).
Now, let's say that the next day, someone submits another instance of this same form, but in the ID field, they type their name instead of entering a number. Solr spits this out and won't index this record because the schema says ID should be numeric, but on this record, it's not.
The way we've been dealing with this so far is to trap the exception we get when a field's data type disagrees with the schema, and then we use the Solr API to alter the schema, making the field in question a text or string instead of a numeric.
Of course, when we do this, we need to reindex the entire collection since the schema changed, and so we need to persist all the original data just in case we need to re-index everything after one of these schema data-type collisions. We're big Solr fans, but at the same time, we wonder whether the benefits of using the search engine outweigh all this extra work that gets triggered if a user simply enters character data in a previously numeric field.
Is there a way to just have Solr always assign something like "text_general" for every field, or is there some other better way?
I would say that you might need to handle the Id values at your application end.
It would be good to add a validation for Id, that Id should be of either string or numberic.
This would resolve your issue permanently. If this type is decided you don't have to do anything on the solr side.
The alternative approach would be have a fixed schema.xml.
In this add a field Id with a fixed fieldType.
I would suggest you to go with string as a fieldType for ID if don't want it to tokenize the data and want the exact match in the search.
If you would like to have flexibility in search for the Id field then you can add a text_general field type for the field.
You can create your own fieldType as well with provided tokenizer and filter according to your requirement for you the field Id.
Also don't use the schemaless mode in production. You can also map your field names to a dynamic field definition. Create a dynamic field such as *_t for the text fields. All your fields with ending with _t will be mapped to this.
I have indexed two json documents into Solr, and when I get the response am I recieving both documents - how to differentiate the two documents and store the documents separately?
You need to define a (unique) key when indexing the json-documents - this key being either mandatory or not. This could be done in schema.xml or managed-schema, if not already done. Further on would you have to search for this key in the query for fetching the wanted document.
This can be compared with querying for a unique primary key in SQL and traditional databases. A tuple/record, uniquely defined by the primary key, would in this scenario be equivalent with the json documents.
Assuming two documents with respective unique id 1 and 2 - can you fetch document 1 by searching forq=id:1 in the Solr Admin-UI - if you want the document with id 1. I'm afraid I don't know how to do this is Solrj or by QueryResponse.
Management of where documents are stored in Solr is not supported - it is more or less black-boxed. This should however not be a problem considering your situation as long as you specify the query correctly.
Look here for a link that tells how to use Solr 6 as a JDBC dataSource . Better if you use Solr 6 if you want to utilize Solr more as a data source rather than an index source as it has enhanced SQL level features and hence, serves the purpose best . Here is the link https://sematext.com/blog/2016/04/26/solr-6-as-jdbc-data-source/ . Let me know if that helps you :) .
I'm working with solr and indexing data from DB.
When I import the data using SQL query, I got some rows with the same key.
I need a way that solr will generate a new field with unique key.
How can I do that?
Thanks
I am not sure if this is possible or not, but maybe you need to re-consider your logic here...
Indexing operation into Solr should be Re-Runable. So, imagine that you come one day and decide to change the schema of your core.
If you generate a new key everytime you import a document, you will end up creating duplicate items when you re-run your data import.
Maybe you need to revisit your DB design to have a unique key, or maybe in the select query, you can create a derived or calculated column value that is calculated based on multiple columns. But I am sure that pushing this problem to solr is not the solution.
ideally the unique key should come from the db (are you sure you cannot get one, by composing some columns etc?).
But, if you cannot, Solr supports UUID generation for this, look here to see how it works depending on your solr version
I am very new to solr.
Initially the "id" in my solr schema was of type string.
I have 30,000 documents, but now I want to use uuid instead of a string.
Simply changing the id to uuid and following instructions from http://wiki.apache.org/solr/UniqueKey
It did not work because it tried to string id as uuid and it failed.
My question is how do i change my id to uuid without deleting any data ?
Any info on this will be helpful.
Hope your id field is be mentioned as uniqueKey in the schema.xml. That means every solr document in your Solr instance must contain the id field. When you modify the type of any field in the schema, the previously created index for those fields get messed up. Now you can't query on those field, though they are still present in your Solr instance.
What good is that if you can not query on the data, you indexed to query? So, there is no good keeping the old document in your Solr, on which you can't query. And this time you have modified the uniqueKey field. So, you must re-index. If you would have modified the type of other field except uniqueKey, then Atomic update or partial update would have been a solution.