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.
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'))
I'm attempting to export data from an older Orchard db and am having problems finding which table the content of a blog post is stored. I've tried using a number of different 'Search all columns' spocs to search all tables and columns but am not finding text from the post itself.
If I have a blog post where the opening sentence is:
This sentence contains a unique word.
I would have expected at least one of the various 'Search all columns' examples to have turned up a table/column. But so far, none have.
thx
Orchard store data based on two tables, ContentItemRecord and ContentItemVersionRecord, which store meta data for content items like BlogPost, and these content items built from multiple parts, each part has it's table and the relation between the item and it's parts is based on Id (if not draftable) or ContentItemRecord_Id (if draftable) columns
if we take BlogPost type as example, which built from TitlePart, BodyPart, AutoroutePart and CommonPart, and you want to select all the data of post (id = 90), then you can find it's title in TitlePartRecord table (ContentItemRecord_Id = 90), and the body text of it in BodyPartRecord table with same relation as title part record, and the route part in AutorouteRecord table with same relation, and the common meta data in CommonPartRecord (Id = 90).
This is the way to extract data from Orchard database, hope this will help you.
Tnx to #mdameer...
and the related query of madmeer's answer is this:
SELECT * FROM dbo.default_Title_TitlePartRecord
inner join dbo.default_Orchard_Framework_ContentItemRecord on
dbo.default_Title_TitlePartRecord.ContentItemRecord_id=dbo.default_Orchard_Framework_ContentItemRecord.Id
inner join dbo.default_Common_BodyPartRecord on
dbo.default_Common_BodyPartRecord.ContentItemRecord_id=dbo.default_Orchard_Framework_ContentItemRecord.Id
where dbo.default_Title_TitlePartRecord.ContentItemRecord_id=90
and this is the rightsolution
Just in case it may be useful for others, the following is the actual SQL query used to migrate an Orchard instance to Umbraco. It is derived from the excellent answers by mdameerand and Iman Salehi:
SELECT t.Title, f.Data, b.Text FROM dbo.Title_TitlePartRecord t
inner join dbo.Orchard_Framework_ContentItemRecord f on
t.ContentItemRecord_id=f.Id
inner join dbo.Common_BodyPartRecord b on
b.ContentItemRecord_id=f.Id
AND b.Id = (
SELECT MAX(m2.Id)
FROM dbo.Common_BodyPartRecord m2
WHERE m2.ContentItemRecord_id = f.Id
)
AND t.Id = (
SELECT MAX(m2.Id)
FROM dbo.Title_TitlePartRecord m2
WHERE m2.ContentItemRecord_id = f.Id
)
I seem to be stuck on a classic ORM issue and don't know really how to handle it, so at this point any help is welcome.
Is there a way to get the pivot table on a hasManyThrough query? Better yet, apply some filter or sort to it. A typical example
Table products
id,title
Table categories
id,title
table products_categories
productsId, categoriesId, orderBy, main
So, in the above scenario, say you want to get all categories of product X that are (main = true) or you want to sort the the product categories by orderBy.
What happens now is a first SELECT on products to get the product data, a second SELECT on products_categories to get the categoriesId and a final SELECT on categories to get the actual categories. Ideally, filters and sort should be applied to the 2nd SELECT like
SELECT `id`,`productsId`,`categoriesId`,`orderBy`,`main` FROM `products_categories` WHERE `productsId` IN (180) WHERE main = 1 ORDER BY `orderBy` DESC
Another typical example would be wanting to order the product images based on the order the user wants them to
so you would have a products_images table
id,image,productsID,orderBy
and you would want to
SELECT from products_images WHERE productsId In (180) ORDER BY orderBy ASC
Is that even possible?
EDIT : Here is the relationship needed for an intermediate table to get what I need based on my schema.
Products.hasMany(Images,
{
as: "Images",
"foreignKey": "productsId",
"through": ProductsImagesItems,
scope: function (inst, filter) {
return {active: 1};
}
});
Thing is the scope function is giving me access to the final result and not to the intermediate table.
I am not sure to fully understand your problem(s), but for sure you need to move away from the table concept and express your problem in terms of Models and Relations.
The way I see it, you have two models Product(properties: title) and Category (properties: main).
Then, you can have relations between the two, potentially
Product belongsTo Category
Category hasMany Product
This means a product will belong to a single category, while a category may contain many products. There are other relations available
Then, using the generated REST API, you can filter GET requests to get items in function of their properties (like main in your case), or use custom GET requests (automatically generated when you add relations) to get for instance all products belonging to a specific category.
Does this helps ?
Based on what you have here I'd probably recommend using the scope option when defining the relationship. The LoopBack docs show a very similar example of the "product - category" scenario:
Product.hasMany(Category, {
as: 'categories',
scope: function(instance, filter) {
return { type: instance.type };
}
});
In the example above, instance is a category that is being matched, and each product would have a new categories property that would contain the matching Category entities for that Product. Note that this does not follow your exact data scheme, so you may need to play around with it. Also, I think your API query would have to specify that you want the categories related data loaded (those are not included by default):
/api/Products/13?filter{"include":["categories"]}
I suggest you define a custom / remote method in Product.js that does the work for you.
Product.getCategories(_productId){
// if you are taking product title as param instead of _productId,
// you will first need to find product ID
// then execute a find query on products_categories with
// 1. where filter to get only main categoris and productId = _productId
// 2. include filter to include product and category objects
// 3. orderBy filter to sort items based on orderBy column
// now you will get an array of products_categories.
// Each item / object in the array will have nested objects of Product and Category.
}
Say I have a stored procedure that returns dataSet from 2 different tables. Example:
SELECT Customers.FirstName, Customers.LastName, SUM(Sales.SaleAmount) AS SalesPerCustomer
FROM Customers LEFT JOIN Sales
ON Customers.CustomerID = Sales.CustomerID
GROUP BY Customers.FirstName, Customers.LastName
Is there any way to get a strongly typed list as a result from this stored procedure ? Something like this:
StoredProcedure sp = myDevDB.GetCustomerSales();
List<MyCustomType> resultSet = sp.ExecuteTypedList<MyCustomType>();
How and where do I define the MyCustomType class ? How do I map its properties to the actual table columns ?
thanks,mehul
I solved it by creating a class (in the same place as all my other classes, but I didn't extend IActiveRecord, it's just a vanilla class).
Make sure the property names have exactly the same name and data type as the ones in the procedure, then call db.sproc(params).ExecuteTypedList().AsQueryable(); and it populated fine.
I have two tables. Both of them have a column named 'title'. When I use the following code snippet to join two tables, I can't access one of the title column.
$select = $this->select(Zend_Db_Table::SELECT_WITH_FROM_PART);
$select->setIntegrityCheck(false);
$select->join("service","service.id = lecture.service_id");
return $select;
is there a way to access both columns?
You need to rename one of the columns so it doesn't conflict with the other. If you pass an array as the optional 3rd argument to join(), you can specify which columns to retrieve from the joined table. If one or more of the entries in the array is hashed, then the hash key will be used as the property name. With the code below, you can refer to the title column of the service table as "service_title" in your query results. If you want other columns from the service table, add them to the array, with or without hashes as desired.
$select = $this->select(Zend_Db_Table::SELECT_WITH_FROM_PART);
$select->setIntegrityCheck(false);
$select->join("service", "service.id = lecture.service_id",
array("service_title" => "service.title");
return $select;
$select = $this->select();
$select->from(array('t'=>'table1'), array('table_title AS title_first','table_sendo_colun','table_third_colun'));
$select->setIntegrityCheck(false);
$select->join("service","service.id = t.service_id");
return $select;
Maybe It can do the job.
Regard´s.