Is there any way to used embeds_many in Ecto without having an id / primary_key field?
My database depends on having a unique index on this field, and ecto automatically inserting keys breaks this requirement.
Yes. embeds_many in Postgres ends up as an array of JSON. Define a module that represents that JSON data and in the definition of the embedded_schema use #primary_key false. For example, suppose you wanted to store an array of key/value pairs on each row. Let's call them Tags. You could define that like below and you'd have no generated primary key on each element in the array. You could have another field within that schema which would be populated in whatever way makes sense for your app.
defmodule MyApp.Tag do
use MyApp.Web, :model
#primary_key false
embedded_schema do
field :key, :string
field :value, :string
end
def changeset(struct, params \\ %{}) do
struct
|> cast(params, [:key, :value])
|> validate_required([:key])
end
end
Related
Working on Azure Cognitive Search with backend as MS SQL table, have some scenarios where need help to define a query.
Sample table structure and data :
Scenarios 1 : Need to define a query which will return data based on category.
I have tied query using search.ismatch but its uses prefix search and matches other categories as well with similar kind of values i.e. "Embedded" and "Embedded Vision"
$filter=Region eq 'AA' and search.ismatch('Embedded*','Category')
https://{AZ_RESOURCE_NAME}.search.windows.net/indexes/{INDEX_NAME}/docs?api-version=2020-06-30-Preview&$count=true&$filter=Region eq 'AA' and search.ismatch('Embedded*','Category')
And it will response with below result, where it include "Embedded" and "Embedded Vision" both categories.
But my expectation is to fetch data only if it match "Embedded" category, as highlighted below
Scenario 2: For the above Scenario 1, Need little enhancement to find records with multiple category
For example if I pass multiple categories (i.e. "Embedded" , "Automation") need below highlighted output
you'll need to use a different analyzer which will break the tokens on every ';' just for the category field rather than 'whitespaces'.
You should first ensure your Category data is populated as a Collection(Edm.String) in the index. See Supported Data Types in the official documentation. Each of your semicolon-separated values should be separate values in the collection, in a property called Category (or similar).
You can then filter by string values in the collection. See rules for filtering string collections. Assuming that your index contains a string collection field called Category, you can filter by categories containing Embedded like this:
Category/any(c: c eq 'Embedded')
You can filter by multiple values like this:
Category/any(c: search.in(c, 'Embedded, Automation'))
Start with clean data in your index using proper types for the data you have. This allows you to implement proper facets and you can utilize the syntax made specifically for this. Trying to work around this with wildcards is a hack that should be avoided.
To solve above mention problem used a below SQL function which will convert category to a json string array supported by Collection(Edm.String) data type in Azure Search.
Sql Function
CREATE FUNCTION dbo.GetCategoryAsArray
(
#ID VARCHAR(20)
)
RETURNS NVARCHAR(MAX)
AS
BEGIN
DECLARE #result NVARCHAR(MAX) = ''
SET #result = REPLACE(
STUFF(
(SELECT
','''+ TRIM(Value) + ''''
FROM dbo.TABLEA p
CROSS APPLY STRING_SPLIT (Category, ';')
WHERE p.ID = #ID
FOR XML PATH('')
),1,1,''),'&','&')
RETURN '[' + #result + ']'
END
GO
View to use function and return desired data
CREATE View dbo.TABLEA_VIEW AS
select
id
,dbo. GetCategoryAsArray(id) as CategoryArr
,type
,region
,Category
from dbo.TABLEA
Defined a new Azure Search Index using above SQL View as data source and during Index column mapping defined CategoryArr column as Collection(Edm.String) data type
Query to use to achieve expected output from Azure Search
$filter=Region eq 'AA' and CategoryArr/any(c: search.in(c, 'Embedded, Automation'))
SelectedFields is the list of the fields having API Name and itr the iterative variable and similarly rec is the iterator variable for the records So whenever I am using {!itr}
in the facet then it will print API name and If do not use facet then it will print label of the fields how to fix this??
<apex:repeat value="{!selectedFields}" var="itr">
<apex:column value="{!rec[itr]}">
<apex:facet name="header">
<apex:commandLink action="{!sortByColumn}" reRender="recPage">{!itr}
<apex:param name="Names" value="{!itr}" assignTo="{!sortingValues}"/>
</apex:commandLink>
</apex:facet>
</apex:column>
Can you use $SobjectType to get the field label, something like {!$ObjectType.Account.fields[itr].label}?
Alternatively in apex build a Map<String, String> where key is the api name and value is the label. Or you can even iterate over list of field tokens, not strings. sObject class supports a dynamic get with field token as param so same trick should work in VF and you can get label out of a token too.
Yeah! {!$ObjectType.Account.fields[itr].label} It is the way to get the Label from the API name of Objects and For the dynamic objects. We can use this {!$ObjectType[sObject].fields[itr].label} as it will take out the label from the API names.
I have 3 fields
Pick_no= fields.many2one(stock.picking)
Partner_id= field.char
Location_id=field.char
I want to auto fill partner and location fields based on the selected pick_id.
What should I use onchange or depends?
IMO You may use onchange() method.
Need to change field datatype. Go to stock.picking model and verify datatype. In your case, you declared with char. It is not wrong but not advisable. If you want to keep char then assign char value, not ID.
partner_id = fields.Many2one(res.partner)
location_id = fields.Many2one(stock.location)
I have to update in C# code using MongoDB. Here I had implement 2nd level array of update in below (subBranchindex is taken in a generic list object):-
for (var index = 0; index < subBranchindex.Count; index++)
{
if (subBranchindex[index]._id == new ObjectId(subBranchid))
{
IMongoQuery queryEdit = Query.EQ("BranchOffice.SubBranchlist._id", new ObjectId(subBranchid));
UpdateBuilder update = Update.Set("BranchOffice.$.SubBranchlist."+ index +".Name",subBranch.SubName).
SafeModeResult s = dc.Collection.Update(queryEdit, update,
UpdateFlags.None, SafeMode.True);
}
}
Here 2nd level array, I was using (for loop Statement) to taken Index value for array. Next I can use 3rd, 4th and 5th level of array means more than (for loop statement) will be assign. So don't need [for loop Statement] and also don't need to assign hardcore number in index.
For example: ("BranchOffice.$.SubBranchlist.0.Name",subBranch.SubName). Here Don't Hardcore number[index] 0 or 1 or 2. "2nd" level array more than 100 record is there.
Is there any way I can use to array index value? Please explain how to solve this probelm. Please explain me with Example.
Based on your example above, my understanding of your schema is the following:
The top-level document has a BranchOffice field
BranchOffice is an array of objects
Each object within BranchOffice has an _id, SubName and SubBranchlist field
SubBranchlist is an array of objects
Each object within SubBranchlist has a Name field
Your update statement appears to be copying the SubName field to each Name field among objects within SubBranchlist (a sibling field of SubName).
Using the property path syntax to select fields through arrays (e.g. SubBranchlist.0.Name), there is no "wildcard" index that will allow you to modify Name fields among all objects in the array.
On a somewhat related note, the $ positional operator only applies to the first-matched array element, so you cannot use that to update multiple array elements. In your case, it would not be an option anyway, since you're using the positional operator for the BranchOffice array field.
You can either issue a series of update queries (for each element in SubBranchlist), or consider using $set to modify the entire SubBranchlist array in one query. The downside with using $set is that you'll need to read and write back the entire array, which may be a problem if other, concurrent operations are also issuing updates to the array.
I am creating BOOK_Issue table which will contain id of person to whom the book is issued.
i have a column name user_id witch will contain ids from tbl_student as well as tbl_faculty. so how to set user_id field of book_issue table with reference to two primary key columns.
Your database schema is not correct.
If you expect unique IDs then they should be in one table.
You can create a table with all the users, and have a column to set their type (student, faculty). Then create 2 different tables for each type that has the proper information for each user based on their type.
Create a "person" superclass that can be either of type "student" or type "faculty". Reference this from the BOOK_Issue table instead.
Basically to create this relationship, you'll need one unique ID that spans both "student" and "faculty". Put this in a table (tbl_person?) and have each row in tbl_student and tbl_faculty reference this new table. It's probably also best to then pull out the fields present in both tbl_student and tbl_faculty and put them in this new supertable instead.
You can solve the problem by either having an extra column in BOOK_Issue table, next to user_id, which indicates if this is a Student ID or a Faculty ID.
Alternatively, the IDs themselves may readily include some pattern which indicate their nature (for example no all faculty Ids may start with say "UC", and none of the student Id are so).
The two solutions above then allow using queries similar to the following
SELECT B.*,
CASE B.BorrowerType -- could be LEFT(user_id, 2) etc...
WHEN 'S' THEN S.Name
WHEN 'F' Then F.Name
END As Name,
CASE B.BorrowerType
WHEN 'S' THEN S.PhoneNumber
WHEN 'F' Then F.Phone -- Note that these constructs allow
-- mapping distinct columns names etc.
END As PhoneNr
FROM BOOK_Issue B
LEFT JOIN tbl_student S ON B.BorrowerType = 'S' AND B.user_id = S.id
LEFT JOIN tbl_faculty F ON B.BorrowerType = 'F' AND B.user_id = F.id
WHERE B.DueDate < '11/23/2009' -- or some other condition
This can get a bit heavy when we need to get multiple columns from the student/faculty tables. A possible alternative is a UNION, but this would then cause the repeating of the search clause.
Finally, the best solution but not avaible on all DBMS is a sub-query driven by an "IF B.BorrowerType = 'S' " condition.
This should be your table design:
FacultyTable (FacultyID, FacultyName)
StudentsTable (StudentID, StudentName, FacultlyID, ...)
BookTable (BookID, BookName, ...)
UsersTable(UserID, UserName, UserPassword, StudentID, LastLogin, ...)
Now this is the main thing:
BookIssedTable(BookIssedID, BookID, UserID)
//This table tells me that a book of "BookID was issued to a user of "UserID"
//this can be better for this is certainly a great improvement from the initial design.