in my type policy
typepolicies:{
Query:{
fields:{
getCartItems:{
//This is a local field
//I want to reference "allProducts" field here
},
allProducts:{
//Products are ferched from network and cached
}
}
}
}
in my getCartItems I have a reactive var of product ids array which I want to loop over and filter out matching products with matching ids from all products field. Is there any way to reference siblings of Query fields.
Related
I've following dynamoDB table
user_id
date
game
user1
2021-12-06 14:36:46
game1
user1
2021-12-06 15:36:46
game1
user1
2021-12-07 11:36:46
game2
user1
2021-12-07 12:36:46
game2
partition key: user_id
sort key: date
I want to Query the latest entry of user for game game1
(Which is the second item from table with date 2021-12-06 15:36:46). I can achieve this from code as follows;
expr, _ := expression.NewBuilder().
WithKeyCondition(expression.Key("user_id").Equal(expression.Value("user1"))).
WithFilter(expression.Name("game").Equal(expression.Value("game1"))).
Build()
var queryInput = &dynamodb.QueryInput{
KeyConditionExpression: expr.KeyCondition(),
ExpressionAttributeNames: expr.Names(),
ExpressionAttributeValues: expr.Values(),
FilterExpression: expr.Filter(),
ScanIndexForward: aws.Bool(false),
TableName: aws.String(table),
}
This returns me all items of user user1 for game game1. Problem occurs when I apply limit=1 Limit: aws.Int64(1) in QueryInput, it returns nothing. Could someone explain why is that so ?
When I change Limit: aws.Int64(4) (total number of items in table), only then the query returns single expected item. How is this limit working ?
Do I need to use game as GSI ?
The limit on a DDB parameter is applied before your filter expressions.
Essentially with a limit of 1, it retrieves 1 record, then applies the filters and returns you the items that match (0).
See https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Query.html#Query.Limit for more details, copied in case link breaks
Limiting the Number of Items in the Result Set
The Query operation allows you to limit the number of items that it reads. To do this, set the Limit parameter to the maximum number of items that you want.
For example, suppose that you Query a table, with a Limit value of 6, and without a filter expression. The Query result contains the first six items from the table that match the key condition expression from the request.
Now suppose that you add a filter expression to the Query. In this case, DynamoDB reads up to six items, and then returns only those that match the filter expression. The final Query result contains six items or fewer, even if more items would have matched the filter expression if DynamoDB had kept reading more items.
I have the table "SYMPTOMS" with two fields:
"ID" number and "SYMPTOM" varchar2(1000).
I want on my page the item "P2117_SYMPTOM_ID" to be autocomplete and search from the second field ("SYMPTOM") but to return the ID value of this record.
Check the docs. The page item type "Text field with autocomplete" only takes a single column as source (a return value), not 2 columns like a list of values. Reason is that this is an enhanced text field: you can freely enter data but it will suggest you possibilities from a list. A text field only has its actual value as return type too. You could have return ids from a table but then how would you handle values entered by the user that are not in the list ? If you want to map the data the user enters to an id then you can write your own function to do that. Ideally that function would:
Return the id of the value if it exists
Create a new value and return that newly created id if it doesn't exist.
The items in my table have an attribute of type string set. I'll stick to the example from the documentation and call the set "colors". As the name indicates the set holds various strings representing colors in each item. This would look like
this.
Now I want to query the table so that I retrieve all items where a specific color is within the set. So in regards to the attached picture I would like to query for the color "Green" and want to receive the items Picture2 and Picture3.
Is there a way to do this?
Since the amount of all possible colors and items is huge plus the fact that only a very small amount of colors are associated to an item, a scan would be very inefficient. So far I tried to create a global secondary index (GSI) but it seems that its not possible in the way I want it or am I wrong?
Unless the field you are searching for is built into the primary key or secondary index, scan will be your only option.
The scan operation will allow you to use the contains keyword to search the set
let params = {
TableName : 'TABLE_NAME',
FilterExpression: "contains(#color, :color)",
ExpressionAttributeNames: {
"#color": "color",
},
ExpressionAttributeValues: {
":color": "Blue",
}
};
documentClient.scan(params, function(err, data) {
console.log(data);
});
According to the docs on secondary indexes, you cannot build an index using a set as the primary key
The key schema for the index. Every attribute in the index key schema must be a top-level attribute of type String, Number, or Binary. Other data types, including documents and sets, are not allowed.
I noticed that DynamoDB query/scan only returns documents that contain a subset of the document, just the key columns it appears.
This means I need to do a separate Batch_Get to get the actual documents referenced by those keys.
I am not using a projection expression, and according to the documentation this means the whole item should be returned.1
How do I get query to return the entire document so I don't have to do a separate batch get?
One example bit of code that shows this is below. It prints out found documents, yet they contain only the primary key, the secondary key, and the sort key.
t1 = db.Table(tname)
q = {
'IndexName': 'mysGSI',
'KeyConditionExpression': "secKey= :val1 AND " \
"begins_with(sortKey,:status)",
'ExpressionAttributeValues': {
":val1": 'XXX',
":status": 'active-',
}
}
res = t1.query(**q)
for doc in res['Items']:
print(json.dumps(doc))
This situation is discussed in the documentation for the Select parameter. You have to read quite a lot to find this, which is not ideal.
If you query or scan a global secondary index, you can only request
attributes that are projected into the index. Global secondary index
queries cannot fetch attributes from the parent table.
Basically:
If you query the parent table then you get all attributes by default.
If you query an LSI then you get all attributes by default - they're retrieved from the projection in the LSI if all attributes are projected into the index (so that costs nothing extra) or from the base table otherwise (which will cost you more reads).
If you query or scan a GSI, you can only request attributes that are projected into the index. GSI queries cannot fetch attributes from the parent table.
I have a DynamoDB table where one of the fields is an array of structures, each structure has several fields, let's say name and phone number. I want to make a (python, but it does not really matter) scan query for entries where one of the array entry's fields is the name that I need. Is that possible ? It is similar to the question
dynamodb - scan items by value inside array
but in my case condition has to be on one of the fields of the structure:
FilterExpression: "contains(#user, :v)",
ExpressionAttributeNames: { "#users": "user" },
ExpressionAttributeValues: { ":v": "John" }
Thanks.