I'm trying to reference a Twig expression inside another expression:
{{ dbquery('name', 'product_manufacturer_translation', {'product_manufacturer_id =' lineItem.payload.manufacturerId} ) }}
Here, lineItem.payload.manufacturerId is the Twig expression I'm trying to put into the dbquery - but this does not work. Thanks for sharing your thoughts!
Edit: this query does not yield a result. What I would expect is a product manufacturer name, based on the product manufacturer ID. The manufacturerId experssion itself, when used on its own, does yield a result. I know there is a database record that should match this query, too.
Related
How do we write conditions in arango, that includes for loops. I can elaborate the requirement below.
My requirement is if a particular attribute(array type) exists in the arango collection, i would read data from the collection(that requires a loop) or else, might do the following :
return null
return empty string ""
do nothing.
Is this possible to achieve in arango?
The helping methods could be -->
-- has(collectionname, attributename)
-- The ternary operator ?:
let attribute1 = has(doc,"attribute1") ?(
for name in doc.attribute1.names
filter name.language == "xyz"
return name.name
) : ""
But this dosent work. Seems like arango compiler first attempts to compile the for loop, finds nulls and reports error as below. Instead, it should have compiled "has" function first for the ternary operator being used.
collection or array expected as operand to FOR loop; you provided a value of type 'null' (while executing)
If there is a better way of doing it, would appreciate the advice!!
Thanks in advance!
Nilotpal
Fakhrany here from ArangoDB.
Regarding your question, this is a known limitation.
From https://www.arangodb.com/docs/3.8/aql/fundamentals-limitations.html:
The following other limitations are known for AQL queries:
Subqueries that are used inside expressions are pulled out of these
expressions and executed beforehand. That means that subqueries do not
participate in lazy evaluation of operands, for example in the ternary
operator. Also see evaluation of subqueries.
Also noted here for the ternary operator:
https://www.arangodb.com/docs/3.8/aql/operators.html#ternary-operator.
An answer to the question what to do may be to use a FILTER before enumerating over the attributes:
FOR doc IN collection
/* the following filter will only let those documents passed in which "attribute1.names" is an array */
FILTER IS_ARRAY(doc.attribute1.names)
FOR name IN doc.attribute1.names
FILTER name.language == "xyz"
RETURN name.name
Other solutions are also possible. Depends a bit on the use case.
Here is existing code:
knex("products")
.first("id", "name", "ingredients")
...
So, currently it just uses array of column names.
Now I want to add calculated column here. It would consists of "constant" + product.id.
For product with id 1 it would be "api/v1/img/1".
For product with id 222 it would be "api/v1/img/222".
Alias of it should be "image".
I have to use knex.raw somehow. Do not understand how and what is the correct syntax to use it with .first().
I'm sorry, I'm unable to understand the question. What kind of result are you trying to achieve? maybe something like this?
knex("products")
.select('*', knex.raw(`'api/v1/img' || ?? as computed`, ['products.id']))
.first()
Like this: https://runkit.com/embed/9okme0czge8z
We use this syntax to include partial during run time:
{{> (lookup . 'file') }}
file is a var name from the parent file.
I tried to add a prefix to the file name, So I tried:
{{> lookup . 'path/file'}}
{{> (lookup . (strmerge 'path/' 'file')) }}
Note: I made a helper method to merge strings
I tried those and others but nothing worked for me.
Does any one know how to do this?
Thanks
In the code {{> (lookup . 'file') }} we are telling Handlebars that the name of our partial is to be found at the file property of the current context object.
Assuming a context object like { file: 'myPartial' }, the result of the lookup is {{> myPartial }}, which tells Handlebars to render a partial called "myPartial".
If we want to add a prefix to our partial, so that Handlebars will register a partial called "path/myPartial", the simplest way to do this would be to add that path to the value of the file property in the context object. The context object would become: { file: 'path/myPartial' }.
If, for some reason, the "path/" prefix must be added to the template and not the data, then we will need to determine a way to produce the String "path/myPartial" from our current data.
Both of your attempts put "file" in the name of the property to be looked-up. Your code will try to find the property path/file on the context object and this will fail. We will definitely need a helper to concatenate Strings, but it must concatenate "path/" with the value of file, not the literal String, "file".
To achieve our goal we will no longer require the lookup helper. The lookup was needed only because you can't write {{> (file) }} in Handlebars, because Handlebars will treat file as a helper instead of as a variable. However, since we are using a concatenation helper, strmerge, we can use the String it returns as our partial name, without any need for a lookup. The correct code becomes:
{{> (strmerge 'path/' file) }}
It's important to note that file in this example is not in quotes. It is a variable, not a String.
I have created a fiddle for your reference.
I cannot find where to quote a field name that has a space in it, for example when doing
FILTER s._key = a.`Supplier Id`
The above, sql-style quote doesn't work, neither does array access. What's the correct way?
Figured it out now, I got bitten by SQL and forgot that equality comparison is made with == in AQL. Then the array access worked, so the way to use field names with spaces is this:
FILTER s._key == a['Supplier Id']
If the field is without spaces but has some special characters, it works to use backtick instead of array access:
FILTER s._key == a.`ÅterförsäljareId`
Edit: Another option is to use bind variables:
FILTER s._key == a.#field
// Passing this to the API as bind variables:
{
"field": "Supplier Id"
}
I'm currently using node-postgres to query my DB like so:
SELECT DISTINCT(name) FROM users.names ORDER BY name;
I want to return the lowercase of these names, so I've tried this:
SELECT DISTINCT(lower(name)) FROM users.names ORDER BY lower(name);
...but this just returns null in place of each name.
This solved it:
SELECT DISTINCT(LOWER(tag)) AS tag FROM support.tags ORDER BY LOWER(tag);
The key addition is obviously AS tag, otherwise the 'tag' field was renamed to 'lower' in the results set.