I have a few objects created on my database and I need to delete some of the repeating attributes related to them.
The query I'm trying to run is:
UPDATE gemp1_product objects REMOVE ingredients[1] WHERE (r_object_id = '08015abd8002cd68')
But all I get is the folloing error message:
Error querying databse.
[DM_QUERY_E_UPDATE_INDEX]error: "UPDATE: Unable to REMOVE tghe attribute ingredients at index 1."
[DM_OBJECT_W_DELETE_ATTR_POSITION_ERROR]warning: "attempt to delete
non-existent attribute 88"
Object 08015abd8002cd68 exists and I can see it on the database. Queries like SELECT and DELETE work fine but I do not want to delete the whole object.
There is no easy way to do this. The reason is that repeating attributes are ordered, to enable multiple repeating attributes to be synchronized for a given object.
Either
set the attribute value to be empty for the given position, and change your code to discard empty attributes, or
use multiple DQL statements to shuffle the order so that the last one becomes empty, or
change your data model, e.g. use a single attribute as a property bag with pre-defined delimiters.
Details (1)
UPDATE gemp1_product OBJECTS SET ingredients[1] = '' WHERE ...
Details (2)
For each index; first find the value of index+1:
SELECT ingredients
FROM gemp1_product
WHERE (i_position*-1)-1 = <index+1>
ENABLE (ROW_BASED)
Use the value in a new query:
UPDATE gemp1_product OBJECTS SET ingredients[1] = '<value_from_above>' WHERE ...
It should also be possible to do this by nesting DQL somehow, but it might not be worth the effort.
Something is either wrong with your query or with your repository. I think you are mistyping your attribute name or using wrong index in your UPDATE query.
If you google for DM_OBJECT_W_DELETE_ATTR_POSITION_ERROR you'll see on this link a bit more detailed explanation:
CAUSE: Program executed a DeleteAttr operation that specified an non-existent attribute position (either a negative number or a number larger than the number of attributes in the object).
From this you could guess that type isn't in consistent state, or that you are trying to remove too big index of your repeating attribute, etc. Did you checked your repository with Consistency checker Job and other similar Jobs?
As of for the removing of repeating property (sttribute) value with DQL query, this is unachievable with single query since you need to specify index position which you don't know at first. But writing a simple script or doing it manually if it's not big amount of values to delete is the way you want to go.
Related
I have a DynamoDB table with animals and I'm interacting with it using Dynamoose. My table has a 'UserId' attribute, that indicates the user that registered that animal. I want to write a query that finds all the animals registered by the same user, i.e., gets all the items that have the attribute 'UserId' matching the input string.
I'm trying to use Dynamoose's queries like this MyModel.query('UserId').eq(user.id).using('UserId-index').exec();, but it always gives this error Index can't be found for query. I imagine that this is caused because it is not finding the index for the attribute 'UserId', but I have an index 'UserId-index' on my table.
I also tried specifying the index that should be used on the query with the using() method, like this MyModel.query('UserId').eq(user.id).using('UserId-index').exec();, but it gave me this other error: Either the KeyConditions or KeyConditionExpression parameter must be specified in the request, which I don't get at all.
Note that I don't wanna use scan(), as the official documentation highly encourages the developers to use query() instead.
I've been reading a DynamoDB docs and was unable to understand if it does make sense to query on Global Secondary Index with a usage of 'contains' operator.
My problem is as follows: my dynamoDB document has a list of embedded objects, every object has a 'code' field which is unique:
{
"entities":[
{"code":"entity1Code", "name":"entity1Name"},
{"code":"entity2Code", "name":"entity2Name"}
]
}
I want to be able to get all documents that contain entities with entity.code = X.
For this purpose I'm considering adding a Global Secondary Index that would contain all entity.codes that are present in current db document separated by a comma. So the example above would look like:
{
"entities":[
{"code":"entity1Code", "name":"entity1Name"},
{"code":"entity2Code", "name":"entity2Name"}
],
"entitiesGlobalSecondaryIndex":"entityCode1,entityCode2"
}
And then I would like to apply filter expression on entitiesGlobalSecondaryIndex something like: entitiesGlobalSecondaryIndex contains entityCode1.
Would this be efficient or using global secondary index does not make sense in this way and DynamoDB will simply check the condition against every document which is similar so scan?
Any help is very appreciated,
Thanks
The contains operator of a query cannot be run on a partition Key. In order for a query to use any sort of operators (contains, begins with, > < ect...) you must have a range attributes- aka your Sort Key.
You can very well set up a GSI with some value as your PK and this code as your SK. However, GSIs are replication of the table - there is a slight potential for the data ina GSI to lag behind that of the master copy. If the query you're doing against this GSI isn't very often, then you're probably safe from that.
However. If you are trying to do this to the entire table at once then it's no better than a scan.
If what you need is a specific Code to return all its documents at once, then you could do a GSI with that as the PK. If you add a date field as the SK of this GSI it would even be time sorted. If you query against that code in that index, you'll get every single one of them.
Since you may have multiple codes, if they aren't too many per document, you maybe could use a Sparse Index - if you have an entity with code "AAAA" then you also have an attribute named AAAA (or AAAAflag or something.) It is always null/does not exist Unless the entities contains that code. If you do a GSI on this AAAflag attribute, it will only contain documents that contain that entity code, and ignore all where this attribute does not exist on a given document. This may work for you if you can also provide a good PK on this to keep the numbers well partitioned and if you don't have too many codes.
Filter expressions by the way are different than all of the above. Filter expressions are run on tbe data that would be returned, after it is already read out of the table. This is useful I'd you have a multi access pattern setup, but don't want a particular call to get all the documents associated with a particular PK - in the interests of keeping the data your code is working with concise. The query with a filter expression still retrieves everything from that query, but only presents what makes it past the filter.
If are only querying against a particular PK at any given time and you want to know if it contains any entities of x, then a Filter expressions would work perfectly. Of course, this is only per PK and not for your entire table.
If all you need is numbers, then you could do a count attribute on the document, or a meta document on that partition that contains these values and could be queried directly.
Lastly, and I have no idea if this would work or not, if your entities attribute is a map type you might very well be able to filter against entities code - and maybe even with entities.code.contains(value) if it was an SK - but I do not know if this is possible or not
It is possible to use Datastore.key to generate a new key for an element:
const taskKey = datastore.key(['Task', 'sampleTask']);
When running a query, we may get an endCursor that can be used to get the next results.
The cursor is some base64 encoded token that contains the project ID, kind, and key of the last element fetched, with a little bit of unknown binary data.
Would there be a way/method to get that base64 cursor value given the key of an item and kind+project ID?
As previously answered, it's not possible to infer a cursor from a key because a cursor is tied to a query. You can however, filter your queries by key. E.g. select * from Task where key > Key(Task, 'sampleTask')
No, it's not possible.
Or I should rather say that it doesn't make much sense to (attempt to) obtain a cursor from an entity by itself because a cursor only has meaning in the context of the original query from which it was obtained. From Limitations of cursors (emphasis mine):
Cursors are subject to the following limitations:
A cursor can be used only by the same application that performed the original query, and only to continue the same query. To use the cursor
in a subsequent retrieval operation, you must reconstitute the
original query exactly, including the same entity kind, ancestor
filter, property filters, and sort orders. It is not possible to
retrieve results using a cursor without setting up the same query from
which it was originally generated.
Also from Cursors and data updates:
The cursor's position is defined as the location in the result list
after the last result returned. A cursor is not a relative position in
the list (it's not an offset); it's a marker to which Cloud Datastore
can jump when starting an index scan for results.
I am running the following query on Google BigQuery web interface, for data provided by Google Analytics:
SELECT *
FROM [dataset.table]
WHERE
hits.page.pagePath CONTAINS "my-fun-path"
I would like to save the results into a new table, however I am obtaining the following error message when using Flatten Results = False:
Error: Cannot query the cross product of repeated fields
customDimensions.value and hits.page.pagePath.
This answer implies that this should be possible: Is there a way to select nested records into a table?
Is there a workaround for the issue found?
Depending on what kind of filtering is acceptable to you, you may be able to work around this by switching to OMIT IF from WHERE. It will give different results, but, again, perhaps such different results are acceptable.
The following will remove entire hit record if (some) page inside of it meets criteria. Note two things here:
it uses OMIT hits IF, instead of more commonly used OMIT RECORD IF).
The condition is inverted, because OMIT IF is opposite of WHERE
The query is:
SELECT *
FROM [dataset.table]
OMIT hits IF EVERY(NOT hits.page.pagePath CONTAINS "my-fun-path")
Update: see the related thread, I am afraid this is no longer possible.
It would be possible to use NEST function and grouping by a field, but that's a long shot.
Using flatten call on the query:
SELECT *
FROM flatten([google.com:analytics-bigquery:LondonCycleHelmet.ga_sessions_20130910],customDimensions)
WHERE
hits.page.pagePath CONTAINS "m"
Thus in the web ui:
setting a destination table
allowing large results
and NO flatten results
does the job correctly and the produced table matches the original schema.
I know - it is old ask.
But now it can be achieved by just using standard SQL dialect instead of Legacy
#standardSQL
SELECT t.*
FROM `dataset.table` t, UNNEST(hits.page) as page
WHERE
page.pagePath CONTAINS "my-fun-path"
I have following declaration for collection
TYPE T_TABLE1 IS TABLE OF TABLE_1%ROWTYPE INDEX BY BINARY_INTEGER;
tbl1_u T_TABLE1;
tbl1_i T_TABLE1;
This table will keep growing and at the end, will be used in FORALL loop to do insert or update on TABLE_1.
Now there might be cases, where I want to delete a certain element. So i am planning to create a procedure, which will take the KEY (unique) and matched the element if that key is found
PSEDUO CODE
FOR i in tbl1_u.FIST..tbl1_u.LAST
LOOP
if tbl1_u(i).key = key then
tbl1.delete(i);
end if;
END LOOP;
My question is,
Once i delete the particular element, would be collection adjust automatically i.e., the index i would be replaced by next element or would that particular index will remain null/invalid and could possibly give me exception if i use it in FORALL INSERT/UPDATE?
I don't think that i can pass TABLE_1%ROWTYPE object to a procedure, do i have to create a record type ?
Any other tip regarding managing collection for bull delete/update/insert would be appreciate. Remeber, I would be dealing with 2 tables, if i am inserting/updating in table_1 then it means i am deleting it from table_2 and vice-versa.
Given that TABLE_1.KEY is unique you might consider using that as the index to your associative arrays. That way you can delete from the collections using the KEY value, which according to the pseudocode is available when doing the deletions. This would also save you having to iterate through the table to find the KEY you want, as the KEY would be the index - so your "deletion" pseudo-code would become:
tbl1_u.delete(key);
To answer your questions:
Since you're using associative arrays, when an element is deleted there is no "empty" space in the collection. The indexes for the elements, however, don't actually change. Therefore you need to use the collection.PRIOR and collection.NEXT methods to loop through the collection. But again, if you use the KEY value as the index you may not need to loop through the collections at all.
You can pass a TABLE_1%ROWTYPE as a parameter to a PL/SQL procedure or function.
You might want to consider using a MERGE statement which could handle doing the inserts and updates in one step. This might allow you to maintain only a single collection. Might be worth looking in to.
Share and enjoy.