I'm new to couchbase. I'm using Java for this. I'm trying to remove a document from a bucket by looking up its ID with query parameters(assuming the ID is unknown).
Lets say I have a bucket called test-data. In that bucked I have a document with ID of 555 and Content of {"name":"bob","num":"10"}
I want to be able to remove that document by querying using 'name' and 'num'.
So far I have this (hardcoded):
String statement = "SELECT META(`test-data`).id from `test-data` WHERE name = \"bob\" and num = \"10\"";
N1qlQuery query = N1qlQuery.simple(statement);
N1qlQueryResult result = bucket.query(query);
List<N1qlQueryRow> row = result.allRows();
N1qlQueryRow res1 = row.get(0);
System.out.println(res1);
//output: {"id":"555"}
So I'm getting a json that has the document's ID in it. What would be the best way to extract that ID so that I can then remove the queryed document from the bucket using its ID? Am I doing to many steps? Is there a better way to extract the document's ID?
bucket.remove(docID)
Ideally I'd like to use something like a N1q1QueryResult to get this going but I'm not sure how to set that up.
N1qlQueryResult result = bucket.query(select("META.id").fromCurrentBucket().where((x("num").eq("\""+num+"\"")).and(x("name").eq("\""+name+"\""))));
But that isn't working at the moment.
Any help or direction would be appreciated. Thanks.
There might be a better way which is running this kind of query:
delete from `test-data` use keys '00000874a09e749ab6f199c0622c5cb0' returning raw META(`test-data`).id
or if your fields has index:
delete from `test-data` where name='bob' and num='10' returning raw META(`test-data`).id
This query deletes the specified document with given document key (which is meta.id) and returns document id of deleted document if it deletes any document. Returns empty if no documents deleted.
You can implement this query with couchbase sdk as follows:
Statement statement = deleteFrom("test-data")
.where(x("name").eq(s("bob")).and(x("num").eq(s("10"))))
.returningRaw(meta(i("test-data")).get("id"));
You can make this statement parameterized or just execute like that.
Related
I'm trying to display some data which is hosted under a subcollection coll1 that exist in doc1 using this code:
val query = db!!.collection("coll1").document(doc1)
.collection("coll2").orderBy("field1", Query.Direction.ASCENDING)
The problem is when I use this code, the doc1 variable isn't generated yet so I get this error:
Invalid document reference. Document references must have an even number of segments
How can I avoid this error till I generate doc1?
You need to know the exact names of all collections and documents in order to perform a query, so your query should only be performed after you have the string value for doc1 that identified the document where the subcollection has been organized.
I am novice User to Couchbase, I am trying to insert the documents into the default bucket like below.
I found the following 2 ways to insert the json documents in the bucket:
1) Inserting by preparing JsonDocument and upsert into the bucket
StringBuilder strBuilder = new StringBuilder();
strBuilder.append("{'phone':{'y':{'phonePropertyList':{'dskFlag':'false','serialId':1000,'inputTray':{'LIST': {'e':[{'inTray':{'id':'1','name':'BypassTray','amount': {'unit':'sheets','state':'empty','typical':'0','capacity':'100'}");
String LDATA = strBuilder.toString();
Cluster cluster = CouchbaseCluster.create("localhost");
Bucket bucket = cluster.openBucket("default");
JsonObject deviceinfoObj = JsonObject.create().put("phoneinfo", LDATA);
bucket.upsert(JsonDocument.create("phone", deviceinfoObj));
2) Or by using like direct query like SQL
String query = "upsert into default(KEY, VALUE) values(LDATA)"
I am not able to find how to execute the above query like noram sql statement
Example:
Statement st = connection.createStatement();
ResultSet rs = st.executeQuery(query);
How to use N1QLQuery to insert the json document in the Couchbase Bucket.
I found the two ways to fetching the document.
i) Getting the document directly by using document Id
bucket.get("phone").content().get("phoneinfo")
ii) Getting the documents by using N!QueryResultSet
N1qlQueryResult result = bucket.query(N1qlQuery.simple("select * from default;"));
for (N1qlQueryRow row : result) {
System.out.println(row);
}
I got confused with the different approaches for inserting and fetching the documents from/to bucket in the Couchbase.
If I insert the documents by using 1st approach I need to prepare JsonObject with some key and value as a entire jsondocument.
So I think I better to insert the document using the second approach, So I will be able to fetch the documents using N1QLResultSet(2nd approach). but by using first approach I need to get the number of documents in the bucket and and then only I can loop through all the documents
Queries:
1) How to get the selective nested nodes from the document
2) In json document, Should I need to split key-value for each node ant then put in the JSONObject to prepare JSONDocument?
3) How to create a view for the bucket to do fast retrieval?
Why dont you create a simple java pojo and define it as a #Document. Then use CrudRepo to save and retrieve documents from couchbase.
this sample might help you:
https://github.com/maverickmicky/spring-couchbase-cache
I'm having a problem with MongoDB using Java when I try adding documents with customized _id field. And when I insert new document to that collection, I want to ignore the document if it's _id has already existed.
In Mongo shell, collection.save() can be used in this case but I cannot find the equivalent method to work with MongoDB java driver.
Just to add an example:
I have a collection of documents containing websites' information
with the URLs as _id field (which is unique)
I want to add some more documents. In those new documents, some might be existing in the current collection. So I want to keep adding all the new documents except for the duplicate ones.
This can be achieve by collection.save() in Mongo Shell but using MongoDB Java Driver, I can't find the equivalent method.
Hopefully someone can share the solution. Thanks in advance!
In the MongoDB Java driver, you could try using the BulkWriteOperation object with the initializeOrderedBulkOperation() method of the DBCollection object (the one that contains your collection). This is used as follows:
MongoClient mongo = new MongoClient("localhost", port_number);
DB db = mongo.getDB("db_name");
ArrayList<DBObject> objectList; // Fill this list with your objects to insert
BulkWriteOperation operation = col.initializeOrderedBulkOperation();
for (int i = 0; i < objectList.size(); i++) {
operation.insert(objectList.get(i));
}
BulkWriteResult result = operation.execute();
With this method, your documents will be inserted one at a time with error handling on each insert, so documents that have a duplicated id will throw an error as usual, but the operation will still continue with the rest of the documents. In the end, you can use the getInsertedCount() method of the BulkWriteResult object to know how many documents were really inserted.
This can prove to be a bit ineffective if lots of data is inserted this way, though. This is just sample code (that was found on journaldev.com and edited to fit your situation.). You may need to edit it so it fits your current configuration. It is also untested.
I guess save is doing something like this.
fun save(doc: Document, col: MongoCollection<Document>) {
if (doc.getObjectId("_id") != null) {
doc.put("_id", ObjectId()) // generate a new id
}
col.replaceOne(Document("_id", doc.getObjectId("_id")), doc)
}
Maybe they removed save so you decide how to generate the new id.
I have a problem while I'm making a Dynamic Query in Liferay 6. I'm trying to make a query to order JournalArticles based on their view count. The view count is specified in another table (AssetEntry).
I'm stuck with this:
DynamicQuery query = DynamicQueryFactoryUtil.forClass(
JournalArticle.class, "articleParent", PortalClassLoaderUtil.getClassLoader());
//adding criterions
query.add(...);
DynamicQuery dq0 = DynamicQueryFactoryUtil.forClass(AssetEntry.class, "asset",
PortalClassLoaderUtil.getClassLoader())
.setProjection(ProjectionFactoryUtil.property("asset.classPK"))
.add(PropertyFactoryUtil.forName("asset.companyId")
.eqProperty("articleParent.companyId"))
.add(PropertyFactoryUtil.forName("asset.groupId")
.eqProperty("articleParent.groupId"));
query.add(PropertyFactoryUtil.forName("articleParent.resourcePrimKey").in(dq0))
.addOrder(OrderFactoryUtil.desc("asset.viewCount"));
With this I get an error message saying: could not resolve property: asset of: com.liferay.portlet.journal.model.impl.JournalArticleImpl.
If I remove the addOrder-call, this error disappears. How should I add the order statement so the main query is aware of asset.viewCount?
AssetEntryQuery assetEntryQuery = new AssetEntryQuery();
assetEntryQuery.setClassName(JournalArticle.class.getName());
assetEntryQuery.setXXX //adding criterions
assetEntryQuery.setOrderByCol1("viewCount");
List<AssetEntry> assetEntries = AssetEntryServiceUtil.getEntries(assetEntryQuery);
I am afraid that there is no direct way to do this with the DynamicQuery API.
I think you would need to use Service builder Finders i.e. Custom Query with Service builder.
You can't use dynamic query because there is no direct reference from JournalArticle entity to AssetEntry entity.
One possibility is to retrieve ordered ids of articles from the AssetEntry table (basically you dq0), then do another query and do the sorting programatically (you have the ids ordered).
Finally I think that this line
query.add(PropertyFactoryUtil.forName("articleParent.resourcePrimKey").in(dq0))
doesn't do what you think it does. resoucePrimKey is reference to resource table for permissions. You need to use id column.
I have created entities in the datastore. I want to use the index assigned to them by the datstore for queries.
i.e get an iterable back where the id is greater than a given number
e.g.
Query q = new Query("MyEntity");
q.addFilter("id",Query.FilterOperator.GREATER_THAN_OR_EQUAL, startId);
PreparedQuery pq = datastore.prepare(q);
I know I can get back an individual entity back via id - but how to get a list ?
Cheers,
Iterable<Entity> myEntities = pq.asIterable();
List<Entity> myEntitiesInAList = pq.asList(FetchOptions.Builder.withChunkSize(500));
Side note:
"id" is not the name of the key assigned automatically by App Engine. I think you must use __key__ as the property name to do queries on it, and construct a full key as the search parameter, not just the long id.
If your intent is to remember where you left off and continue there on a subsequent query, consider using a query cursor. The example on that page might give you some further options.