Web app is being written in classic ASP with a MSSQL backend. On this particular page, the admin can select 1 or any/all of the employees to assign the project to. I'm trying to figure out a simple way to store the employee IDs of the people assigned to it in one column.
The list of employees is generated from another table and can be dynamic (firing or hiring) so I want the program to be flexible enough to change based on these table changes.
Basically need to know how to assign multiple people to a project that can later be called up on a differen page or from a different query.
Sorry for the n00bish question, but thanks!
Don't store multiple ID's in one column! Create another table with the primary key of your existing table and a single ID that you want to store. You can then insert multiple rows into this new table, creating a 1:m (one to many) relationship. For example, let's look at an order table:
order:
order_id
order_date
and I have a product table...
product:
product_id
product_name
Now, you could go down the road of adding a column to order that let you list the products in the order, but that would be bad form. What you want instead is something like..
order_item:
order_item_id
order_id
product_id
quantity
unit_price
You can then perform a join to get all of the products for a particular order...
select
product.*
from orders
inner join order_item on order_item.order_id = order.order_id
inner join product on product.product_id = order_item.product_id
where orders.order_id = 5
Here's an example order_id of 5, and this will get all of the products in that order.
You need to create another table that stores these values such as. So this new table would store one row for each ID, and then link back to the original record with the original records ID.
Related
I have a table where I have ranked all the rows based on the created date column and have the rank indicated on the table as below
main table
I would like to create a cross-reference table with the golden record as the recurring column and the other two records as associated records as below.
output desired
I would like to know how I can achieve this using SQL.
I have tried creating a seperate table with all ID numbers (Rank = 1) and then joining it with the main table to get the ones with rank 1,2 and 3 associated with it. But it doesnt seem to work as I intend to.
output
I have not tested but something like this should work. You might want to add a name_id field.
select b.id_number,a.id_number
from table a
join table b on a.name=b.name
where b.rank=1
As you save from the image, I have a Packing and a Product table. I want to somehow connect some rows from the product table to the Productlist column of Packing table, so that in future I can add packing in the database and write also what products I have in this packing. How can I achieve this?
If Product List has multiple values in it you should not store them in a single column in the table. You should create a separate table that has PackingTableID and Product so in this new table you would have multiple Products tied to one Package. Then you would join to that table. (a one to many relationship).
Similar to this:
Select PackingTable.PackingTableID , ProductTable.PackageName
From PackingTable
INNER JOIN PackingTableProducts ON PackingTable.PackingTableID = PackingTableProducts.PackingTableID
INNER JOIN ProductTable ON PackingTableProducts.ProductID = ProductTable.ProductID
I have two Hive tables as shown below, along with their columns
Tbl_Customer
Id
Name
Tbl_Cntct
Id
Phone
One Id can have many phone numbers so I have a table
Tbl_All
Id
Name
Phn_List ARRAY
My question is on how to load data from Tbl_Custome and Tbl_Cntct into Tbl_All.
I can do it in PIG, but want to do same in Hive.
Thanks
Insert overwrite table Tbl_All
select cus.id,cus.name,collect_set(ctc.phone)
from Tbl_Customer cus join Tbl_Cntct ctc on cus.id = ctc.id
group by cus.id,cus.name
The collect_set UDAF is a function collects the column into an array with no duplicates.If you want to remain all the value include duplicated ones,use collect_list function
Ok, I am total newbie so bear with me.
Trying to implement an ordering system and wish
to save the orders to the database with LINQ to Entities. I can do it now
but for each new object that is saved to the orders table
a new row is inserted, with new OrderNo for each ProductID where as I obviously
should be able to have multiple ProductID's for each OrderNo.
Everything is very simplified as I am just testing.
I have an orders table with columns as such:
OrderNo PK, Identity specification
Line int PL
ProductID int
and a products table
ProductID int PK
An order entity object is instantiated and its properties
are populated with data from a form which is posted to an action method.
It is then saved to the orders table with the following code:
(DropDownList1Value) has value of an existing ProductID and "DropDownList1Value" is the id of the DropDownList element in view.
[HttpPost]
public ActionResult OrderProcessor()
{
int productId = int.Parse(Request.Form["DropDownList1Value"]);
var order = new Order();
order.ProductID = productId;
context.Orders.AddObject(order);
context.SaveChanges();
return View(order);
}
So the records that are inserted look as such:
Sorry, couldn't line up the values under their respective column name in this editor.
OrderNo Line ProductID
101 0 3
102 0 5
103 0 2
Where as I want something like this:
OrderNo Line ProductID
101 1 3
101 2 5
101 3 2
102 1 2
So I wish to know how can I modify the orders table so it
can have multiple records with same "OrderNo" and just increment for "Line" for diff ProductID's and how do I go about inserting such records with LinQ to Entities where
I will obviously have many ProductId from multiple DropDowLists
and they will all be for the one order.
Currently I have foreign key dependency on ProductID in Products table,
so no record in the Orders table can have ProductID which does not exists in the Products table.
I need to make the table depend on the whole key that is OrderNo + Line
and have the "Line" auto increment.
Or is there a much better way of implementing of what I am after here?
Thanks.
Let me first explain briefly what I understood.
There is an invoice, which contains several products for one order number.
and this is how your invoice looks like:
Order Number: 101
------------------
Sl. Products
1 3
2 5
3 2
Before answering I want to point out that you are taking OrderId from a form (That is from client side) This is a wrong and INSECURE approach. Let the order id be AutoGenerated by database.
I would suggest to tweak your database design a little.
Here is a solution that will work.
Note: I am consedering your database support Auto-Increment, for MS SQL replace it with IDENTITY, for Oracle you need to create a sequence.
Product (
id INT PK AUTO-INCREMENT
);
Order (
id INT PK AUTO-INCREMENT
user-id INT FK # user who purchased
### and other common details Like date of purchase etc.
);
Order-Detail (
id INT PK AUTO-INCREMENT
order-id INT FK # Common order id
pdt-id INT FK # product which was purchased.
);
When you make a purchase:
1. Insert a row in order table
2. Fetch the last inserted id
3. Insert order-id from last step and products which are purchased in Order-Detail table,
Fetch all the orders made by a user:
1. Read from order table.
Fetch all products purchased for an order:
1. Fetch details from Order-Detail
Note: You will get List of products purchased, Use Order-detail.id as "Line"
EDIT:
Thanx to HLGEM's comment
If you think price of a product may change then instead of updating the price add a new row to the table (and flag the old table so that it wont be visible, you can also have a column in new table pointing to old table), thus old purchase will point to old product and new orders will point to updated (new) row.
There is one more approach this problem:
store the current cost of product in order-detail table.
If you are facing difficulty understanding above solution here is another and simpler one.
In Order table, Make a composite primary key including OrderNo and Line.
Whenever inserting into database you will need to generate line number in your code, which you can do by runnign a loop over array of propduct being purchased.
I think it would be better to split your current Order table into two separate tables:
Order table
(PK, Identity specification) OrderId
Perhaps other fields like Invoice address, Delivery address, etc.
OrderLine table
(PK, Identity specification) OrderLineId
(FK to Order table) OrderId
(FK to Product table) ProductId
For both tables you have an Entity in your class model: class Order and class OrderLine and a one-to-many relationship between them, so Order has a collection of OrderLines.
Creating an order with all order lines would then look like this:
var order = new Order();
foreach (var item in collection)
{
var orderLine = new OrderLine()
// Get productId from your DropDownLists
orderLine.ProductId = productId;
order.OrderLines.Add(orderLine);
}
context.Orders.AddObject(order);
context.SaveChanges();
Edit
The MVC MusicStore Tutorial might also help for the first steps to create an order processing system with ASP.NET MVC and Entity Framework. It contains classes for orders and order details (among others) and explains their relationships.
Ok I have a question and it is probably very easy but I can not find the solution.
I have 3 tables plus one main tbl.
tbl_1 - tbl_1Name_id
tbl_2- tbl_2Name_id
tbl_3 - tbl_3Name_id
I want to connect the Name_id fields to the main tbl fields below.
main_tbl
___________
tbl_1Name_id
tbl_2Name_id
tbl_3Name_id
Main tbl has a Unique Key for these fields and in the other table, fields they are normal fields NOT NULL.
What I would like to do is that any time when the record is entered in tbl_1, tbl_2 or tbl_3, the value from the main table shows in that field, or other way.
Also I have the relationship Many to one, one being the main tbl of course.
I have a feeling this should be very simple but can not get it to work.
Take a look at SQL Server triggers. This will allow you to perform an action when a record is inserted into any one of those tables.
If you provide some more information like:
An example of an insert
The resulting change you would like
to see as a result of that insert
I can try and give you some more details.
UPDATE
Based on your new comments I suspect that you are working with a denormalized database schema. Below is how I would suggest you structure your tables in the Employee-Medical visit scenario you discussed:
Employee
--------
EmployeeId
fName
lName
EmployeeMedicalVisit
--------------------
VisitId
EmployeeId
Date
Cost
Some important things:
Note that I am not entering the
employees name into the
EmployeeMedicalVisit table, just the EmployeeId. This
helps to maintain data integrity and
complies with First Normal Form
You should read up on 1st, 2nd and
3rd normal forms. Database
normalization is a very imporant
subject and it will make your life
easier if you can grasp them.
With the above structure, when an employee visited a medical office you would insert a record into EmployeeMedicalVisit. To select all medical visits for an employee you would use the query below:
SELECT e.fName, e.lName
FROM Employee e
INNER JOIN EmployeeMedicalVisit as emv
ON e.EployeeId = emv.EmployeeId
Hope this helps!
Here is a sample trigger that may show you waht you need to have:
Create trigger mytabletrigger ON mytable
For INSERT
AS
INSERT MYOTHERTABLE (MytableId, insertdate)
select mytableid, getdate() from inserted
In a trigger you have two psuedotables available, inserted and deleted. The inserted table constains the data that is being inserted into the table you have the trigger on including any autogenerated id. That is how you get the data to the other table assuming you don't need other data at the same time. YOu can get other data from system stored procuders or joins to other tables but not from a form in the application.
If you do need other data that isn't available in a trigger (such as other values from a form, then you need to write a sttored procedure to insert to one table and return the id value through an output clause or using scope_identity() and then use that data to build the insert for the next table.