Does anyone know a simple way of copying multiple table rows and it's related items?
In my simplified example I have two tables, one with a table for companies and one for their employees and I'd like to be able to clone entire companies with all their employees in a simple way.
[Companies]
- ID (Auto-increment)
- Name
[Employees]
- ID
- CompanyID (Foreign Key)
- Name
I've been playing around with the OUTPUT-clause but just managed to return the inserted IDs without a reference to the original row.
I just can't figure out how to link a inserted row to the original one?
If the insert-statement returned a table like this:
#mappingTable
-InsertedCompanyID
-OriginalCompanyID
I could run a statement like this to copy all employees:
INSERT INTO Employees (CompanyID, Name)
SELECT m.InsertedCompanyID, x.Name FROM #mappingTable m
INNER JOIN Employees x (x.CompanyID = m.OriginalCompanyID)
Or am I on the wrong path? Is there's a better way to accomplish this?
You can use the output clause of the merge statment to map between the old ID and the new auto incremented ID.
Have a look at this question: Using merge..output to get mapping between source.id and target.id
Related
I am aware this has been asked multiple times, but for one reason or another the solutions are not working for me.
Database Layout:
I have Table1 (Scanner_Location) Who is getting data pulled from another table/ subform on a form (Scanner IBOB) * Holds Columns: FP#, Count, Location, Model_ID, PK-SL_ID
Table2 (Scanner Detail) Holds Two of the three data columns: (FP#, Location PK-SN)
Table3 (Scanner_Model) Holds the last data column, displayed in a subform. (PK-Model_ID)
The user will input FP#, and location in one section of the form, then navigate to the subform, and select multiple Models, and enter the count (Textbox). Once Selected, they click an 'update' button that executes my queries. (Of which I have an update, AND an Append Query)
The problem is, just using an update query doesn't add the records. And using an Append query creates duplicates of the existing data.
Here's how the flow carries out:
User selects Model 1 and Model 2 with a count of 4 and an FP# of 100. Clicks update.
The queries update, and the information enters correctly.
User Selects the same models again (Model_Select), with the same FP# and count, the Table1 has the same information entered again, with a different primary key.
The goal:
The append query creates duplicates of existing data. I only want my update and/or append queries to:
Update the existing data - Looking for anything with the same FP#
Add any records that do not exist already (Looking at Model_ID and FP#)
INSERT INTO Scanner_Location ( Model_ID, FootPrints_Num, Location_ID, Scanner_Loc_Cnt )
SELECT Scanner_Model.Model_ID, [Forms]![Scanner_IBOB]![fpNum_txt] AS [FP#],
[Forms]![Scanner_IBOB]![Location_Cbo_main] AS Location,
[Forms]![Scanner_IBOB]![Scanner_Loc_CntTxt] AS [Count]
FROM Scanner_Detail
RIGHT JOIN Scanner_Model ON Scanner_Detail.Model_ID = Scanner_Model.Model_ID
WHERE (((Scanner_Model.SM_Acc_Select)=True)
AND ((NOT Exists (SELECT * FROM Scanner_location
WHERE (((Forms!Scanner_IBOB!fpNum_txt)=Forms!Scanner_IBOB!fpNum_txt)
And ((Scanner_Model.SM_Acc_Select)=True)); ))=False));
No query named 'Update_SLoc_Acc53' - there are 'Update_SLoc_Acc3' and 'Update_SLoc_Acc54'. I modified 'Update_SLoc_Acc54' because it is the one called by the code.
The query was not pulling the Location_ID from the combobox. I found the Bound Column was set to 1 and should be 0 to reference the Location_ID column because column index begins with 0. Can hide this column from user by setting width to 0.
This query seems to work:
INSERT INTO Scanner_Location ( Model_ID, FootPrints_Num, Location_ID, Scanner_Loc_Cnt )
SELECT Scanner_Model.Model_ID, [Forms]![Scanner_IBOB]![fpNum_txt] AS FPNum,
[Forms]![Scanner_IBOB]![Location_Cbo_main] AS Location,
[Forms]![Scanner_IBOB]![Scanner_Loc_CntTxt] AS CountMod
FROM Scanner_Model
WHERE (((Scanner_Model.SM_Acc_Select)<>False)
AND (([Model_ID] & [Forms]![Scanner_IBOB]![fpNum_txt] &
[Forms]![Scanner_IBOB]![Location_Cbo_main])
NOT IN (SELECT Model_ID & Footprints_Num & Location_ID FROM Scanner_Location)));
Note I did not use # in field name. Advise not to use punctuation/special characters in names with only exception of underscore. Also used CountMod instead of Count as field name.
Why the requirement to select two models? What if one is added and the other isn't?
I have concerns about the db structure.
Don't think App_Location and App_Detail should both be linking to other tables. Why is Location_ID the primary key in App_Location as well as primary key in Location_Data? This is a 1-to-1 relationship.
Is Serial_Number the serial number for scanner? Why is it a primary key in Telnet? This also results in a 1-to-1 relationship in which case might as well combine them.
If an app is associated with a scanner and scanner is associated with a location then don't need location associated with app. Same goes for scanner and telnet.
Scanner_Location table is not linked to anything. If purpose of this table is to track a count of models/footprints/locations -- as already advised this is usually not a good idea. Ideally, count data should be calculated by aggregate query of raw data records when the information is needed.
Maybe use NOT IN, something like:
[some identifier field] NOT IN (SELECT [some identifier field] FROM
Review EXISTS vs IN
Consider following adjusted append query that checks existence of matched Model_ID and FP_Num in Scanner_Location. If matches do not exist, then query imports selected records as they would be new records and not duplicates. Also, table aliases are used for readability and subquery correlation.
INSERT INTO Scanner_Location ( Model_ID, FootPrints_Num, Location_ID, Scanner_Loc_Cnt )
SELECT m.Model_ID, [Forms]![Scanner_IBOB]![fpNum_txt] AS [FP#],
[Forms]![Scanner_IBOB]![Location_Cbo_main] AS Location,
[Forms]![Scanner_IBOB]![Scanner_Loc_CntTxt] AS [Count]
FROM Scanner_Detail d
RIGHT JOIN Scanner_Model m ON d.Model_ID = m.Model_ID
WHERE ((m.SM_Acc_Select = True)
AND (NOT EXISTS (SELECT 1 FROM Scanner_Location loc
WHERE ((loc.FootPrints_Num = Forms!Scanner_IBOB!fpNum_txt)
AND (loc.Model_ID = m.Model_ID)) ) ));
Say I have a student table with the following fields - student id, student name, age, gender, marks, class.Assume that due to some error, there are multiple entries corresponding to each student. My requirement is to identify the duplicate rows in the table and the filter criterion is the student name and the class.But in the query result, in addition to identifying the duplicate records, I also need to find the original student detail which got duplicated. Is there any method to do this. I went through this answer: SQL: How to find duplicates based on two fields?. But here it only specifies how to find the duplicate rows and not a means to identify the actual row that was duplicated. Kindly throw some light on the possible solution. Thanks.
First of all: if the columns you've listed are all in the same table, it looks like your database structure could use some normalization.
In terms of your question: I'm assuming your StudentID field is a database generated, primary key and so has not been duplicated. (If this is not the case, I think you have bigger problems than just duplicates).
I'm also assuming the duplicate row has a higher value for StudentID than the original row.
I think the following should work (Note: I haven't created a table to verify this so it might not be perfect straight away. If it doesn't it should be fairly close)
select dup.StudentID as DuplicateStudentID
dup.StudentName, dup.Age, dup.Gender, dup.Marks, dup.Class,
orig.StudentID as OriginalStudentId
from StudentTable dup
inner join (
-- Find first student record for each unique combination
select Min(StudentId) as StudentID, StudentName, Age, Gender, Marks, Class
from StudentTable t
group by StudentName, Age, Gender, Marks, Class
) orig on dup.StudentName = orig.StudenName
and dup.Age = orig.Age
and dup.Gender = orig.Gender
and dup.Marks = orig.Marks
and dup.Class = orig.Class
and dup.StudentID > orig.StudentID -- Don't identify the original record as a duplicate
I have a few tables set up in Access as follows (forgive the slightly redundant example content):
Table 1:
- ID
- FirstName
- SecondName
Table 2:
- ID
- Details
- PersonID -> Table 1[ID]
Table 3:
- ID
- Group
- PersonDetails -> Table 2[ID]
Table 1 is the base table containing records and retrieving no other information. For example, it could store someone's first and second names, along with an autonumber ID.
Table 2 contains records which, amongst other things, contain a field that links to Table 1 and stores the ID of one of the records held there. With the lookup wizard I can choose to utilise all fields from Table 1, store the ID of the Table 1 record in the Table 2 field and also display the first and second names in the combobox on the form to make choosing a record more intuitive.
In table 3, I need to store the ID of one of the records in Table 2. However, I would also like to again display in the form combobox the first and second names from the related record (in Table 1) whose ID is stored in Table 2. I can't choose to utilise, for example, the PersonDetails field from table 2 as this just puts ID numbers into the combobox - I'd need to do something equivalent of:
Table 2[ID]->[FirstName]
Is this possible to do with the lookup wizard in Access or would I have to look into queries or VBA?
Thanks.
Your query for your combo should look something like this:
SELECT cp.ID, cp.ReferenceName, c.Company, p.FeePerHour
FROM (ClientProfile AS cp LEFT JOIN Clients AS c ON cp.ClientID = c.ID)
LEFT JOIN Pricing AS p ON cp.PricePlanID = p.ID;
The main problem with your query is that you're missing the Parenthesis that are needed when you have multiple joins. If you had another join, you'd need a second set of parenthesis.
I took some liberty and used table aliases. It makes SQL concise and more readable.
If this query still doesn't work it might be because you're trying to join "child tables" to the "main table" without using your Foreign Key fields as the joining field. If this were my database the SQL would look something like this:
SELECT cp.ClientProfileID, cp.ReferenceName, c.Company, p.FeePerHour
FROM (ClientProfile AS cp LEFT JOIN Clients as C ON cp.ClientID = c.ClientID)
LEFT JOIN Pricing AS p ON cp.ClientProfileID = p.ClientProfileID;
Personally, I basically never use just plain ID as a field name. And when creating a foreign key I usually use the same field name as what the original table has. There are exceptions, especially in the case where you need to link back to the same table more than once. Consider the case where you are tracking real estate properties and you have a Buyer and a Seller that are both entities (but different from each other) in the same People table. You would then need to name them something like BuyerID and SellerID but ultimately they would link back to the PersonID in the Person table.
So Here's the table design I would go for. Notice I changed Group to PriceGroup. Watch out for reserved words when programming, not only in SQL but any language. If you name your field Group at some point you'll be trying to "Group on Group" which sounds and looks bad, if nothing else.
Client:
- ClientID
- FirstName
- SecondName
ClientProfile:
- ClientProfileID
- Details
- ClientID (Foreign Key to Client)
Pricing:
- PricingID
- PriceGroup
- ClientProfileID (Foreign Key to ClientProfile)
i am developing an application in MVC3 using nhibernate
I have a two tables and i want to perform a join between the two and also i want to include multiple where conditions..
I am posting all the tables that are related so that it will clear the requirements:
First table is HobbyMaster:
HobbyId
HobbyName
Second Table is HobbyHome:
HobbyHomeId
HobbyHomeName
Third Table is HobbyDetail:
HobbyDetailId
HobbyId(Foreign Key)
HobbyHomeId(Foreign key)
Fourth Table is HobbyHomeAddress:
Id(primary key)
HobbyHomeId(Foreign key)
StateId(Foreign Key)
DistrictId(Foreign key)
Fifth Table is State:
stateid
statename
last Table is District:
districtid
districtname
I want to write a query like this:
select * from HobbyHomeAddress hobadd,
HobbyDetail hobdet
where hobdet.HobbyId=hobbyid
and hobadd.HobbyId=hobdet.HobbyId
and hobadd.StateId=stateid;
I tried this but it is not working and also gives me NUll
hobbyhomeaddress = session.CreateCriteria(typeof(HobbyHomeAddress))
.CreateAlias("HobbyDetail", "HobbyDetail", NHibernate.SqlCommand.JoinType.InnerJoin)
.Add(Expression.Eq("HobbyID", hobbyid))
.Add(Restrictions.Eq("HobbyHomeAddress.HobbyHomeId", "HobbyDetail.HobbyHomeId"))
.Add(Expression.Eq("ProvincialState.ProvincialStateID", stateid))
.List<HobbyHomeAddress>();
i am able to obtain the id's through ajax but i am not understanding how to fire the following query
Please help me
One possible issue:
.Add(Restrictions.Eq("HobbyHomeAddress.HobbyHomeId", "HobbyDetail.HobbyHomeId"))
This part of the join (in SQL) should be in your nhibernate mappings, you don't need to explicitly specify it.
Downloads table:
id (primary key)
user_id
item_id
created_at
updated_at
The user_id and item_id in this case are both incorrect, however, they're properly stored in the users and items table, respectively (import_id for in each table). Here's what I'm trying to script:
downloads.each do |download|
user = User.find_by_import_id(download.user_id)
item = item.find_by_import_id(download.item_id)
if user && item
download.update_attributes(:user_id => user.id, :item.id => item.id)
end
end
So,
look up the user and item based on
their respective "import_id"'s. Then
update those values in the download record
This takes forever with a ton of rows. Anyway to do this in SQL?
If I understand you correctly, you simply need to add two sub-querys in your SELECT statement to lookup the correct IDs. For example:
SELECT id,
(SELECT correct_id FROM User WHERE import_id=user_id) AS UserID,
(SELECT correct_id FROM Item WHERE import_id=item_id) AS ItemID,
created_at,
updated_at
FROM Downloads
This will translate your incorrect user_ids to whatever ID you want to come from the User table and it will do the same for your item_ids. The information coming from SQL will now be correct.
If, however, you want to update the tables with the correct information, you could write this like so:
UPDATE Downloads
SET user_id = User.user_id,
item_id = Item.item_id
FROM Downloads
INNER JOIN User ON Downloads.user_id = User.import_id
INNER JOIN Item ON Downloads.item_id = Item.import_id
WHERE ...
Make sure to put something in the WHERE clause so you don't update every record in the Downloads table (unless that is the plan). I rewrote the above statement to be a bit more optimized since the original version had two SELECT statements per row, which is a bit intense.
Edit:
Since this is PostgreSQL, you can't have the table name in both the UPDATE and the FROM section. Instead, the tables in the FROM section are joined to the table being updated. Here is a quote about this from the PostgreSQL website:
When a FROM clause is present, what essentially happens is that the target table is joined to the tables mentioned in the fromlist, and each output row of the join represents an update operation for the target table. When using FROM you should ensure that the join produces at most one output row for each row to be modified. In other words, a target row shouldn't join to more than one row from the other table(s). If it does, then only one of the join rows will be used to update the target row, but which one will be used is not readily predictable.
http://www.postgresql.org/docs/8.1/static/sql-update.html
With this in mind, here is an example that I think should work (can't test it, sorry):
UPDATE Downloads
SET user_id = User.user_id,
item_id = Item.item_id
FROM User, Item
WHERE Downloads.user_id = User.import_id AND
Downloads.item_id = Item.import_id
That is the basic idea. Don't forget you will still need to add extra criteria to the WHERE section to limit the rows that are updated.
i'm totally guessing from your question, but you have some kind of lookup table that will match an import user_id with the real user_id, and similarly from items. i.e. the assumption is your line of code:
User.find_by_import_id(download.user_id)
hits the database to do the lookup. the import_users / import_items tables are just the names i've given to the lookup tables to do this.
UPDATE downloads
SET downloads.user_id = users.user_id
, downloads.item_id = items.items_id
FROM downloads
INNER JOIN import_users ON downloads.user_id = import_users.import_user_id
INNER JOIN import_items ON downloads.item_id = import_items.import_item_id
Either way (lookup is in DB, or it's derived from code), would it not just be easier to insert the information correctly in the first place? this would mean you can't have any FK's on your table since sometimes they point to one table, and others they point to another. seems a bit odd.