I've read this link here, but this guy is doing a one off copy from 1st normal form to 3rd, so that's not what I'm doing: StackOverflowPosting
I am going from 3rd normal form to 3rd normal form, pretty much the same design, on a daily basis, only copying hte new data.
Example Data
Parent
ParentId
Created Date
Child
ChildId
Created Date
FK_to_ParentId
Child Data
GrandChild1
GrandChild1Id
FK_to_ChildId
GrandChild1Data
GrandChild2
GrandChild2Id
FK_to_ChildId
GrandChild2Data
So Far, I have
A DataFlow that will pull back all
the Parents after a certain Date.
A DataFlow that will pull back all
the Child Tables created after a
certain date, with a lookup to
find the 'new' FK in the new
database.
Now I need to pull back
grand child1 and so on, but I
don't want to pull them'all' back,
do a look up, and throw away the ones
I already have, I only want to pull
back the ones I need.
Any Ideas?
In the end, I've just used a inner join using Date and time where available, but when I get the data, I have to do a lookup to find the 'new' FK Id to put in the child & grand child tables. Which means the data for Parent, and Child still needs to contain the 'old' ID, but that is ok. so for a Child table, you end up with something that looks like this:
Data Source -> Lookup using the current FK on the parent table to find the new parent's PK, adding in what makes it unique [replace the FK with the PK you just found] -> data store.
Related
This is truly baffling.
I have a subform that is set up as a continuous form and receives data from a query. Here is the SQL
SELECT Top 12 Tbl_Parent_ITN.ID, Tbl_Parent_ITN.ITN_Number, Tbl_Child_ITN.ITN,
Tbl_Child_ITN.Parent_ITN_fk, Tbl_Scope_Rqmts.Completed, Tbl_Scope_Rqmts.Child_ITN_fk,
Tbl_Lkup_Requirements.Requirement, Tbl_Lkup_Basis.Basis
FROM Tbl_Parent_ITN INNER JOIN (Tbl_Lkup_Requirements
INNER JOIN (Tbl_Lkup_Basis INNER JOIN (Tbl_Child_ITN INNER JOIN Tbl_Scope_Rqmts
ON Tbl_Child_ITN.Id = Tbl_Scope_Rqmts.Child_ITN_fk) ON Tbl_Lkup_Basis.ID = Tbl_Scope_Rqmts.Basis_fk)
ON Tbl_Lkup_Requirements.ID = Tbl_Scope_Rqmts.Requirements_fk)
ON Tbl_Parent_ITN.ID = Tbl_Child_ITN.Parent_ITN_fk
WHERE (((Tbl_Parent_ITN.ID)=[Forms]![Frm_Parent_ITN_Main]![parent_id]));
The criteria in the where clause of the SQL is passed based on the control in the form that precedes this form. The value is the primary key of the parent table that joins with several child tables to get all of the data for the subform.
When I open the with one record that has children it works perfectly fine and the form populates with 12 records. However, when I go run the same operation on the next parent record I don't get any results in view even though that parent has 4 child records.
What is really perplexing is that when I run the query independently from opening the form it gives me the exact results that I want based on that 2nd parent record. Furthermore, if I change the subform to a datasheet I still don't get any records; however, I can see the results in the filters of the datasheet form if I select those column headers (but no records show in the form itself). The properties of the subform are the exact same in both cases, so I can't understand what would cause the records to show in the 1st case but not the 2nd??
A few suggestions:
1. Try to do a Me.Refresh to see what happens.
2. Put a break point in the form's OnError event to see is there is something wrong.
3. Check if there is any other data source that may be locking any data that should be refreshed.
4. Verify that the no properties that define the parent-child relationship of the data is being changed during runtime.
5. Check if the parent record id gets refreshed on the OnCurrent event of the form.
Hope this helps,
FunkSoulBrother
Hi all,
I have 3 tables in an access 2010 database:
Crew: CrewID; Name; Adres;...
Voyage: VoyageId; Voyage name; Departure harbour; Arrival harbour
Crewlist: CrewlistId, VoaygeId, CrewId, Rank
The VoaygeId and CrewId from the Crewlist table are linked (relation) to the autonumber ID's from tables 2 and 1.
My first and main question is: Upon boarding everyone has to ‘sign in’ selecting the voyage and there name, and assign them a roll (of to be donde by the responsible officer). How can I make a form that lets the users browse through the voyagenames and crewnames in stead of the ID’s uses in the ‘mother’ table (table 3: Crewlist)
2nd question: how can I make sure that someone isn’t enrolled twice for the same voyage (adding same voyagenumber and same crewId number in crewlist). This would preferably be blocked upon trying to add the same person a second time on a voyage.
To prevent duplicates in Crewlist, add a unique index to the table on both CrewId and VoyageId
It would be a good idea to add relationships and enforce referential integrity
You are now in a position to use the wizards to create a form based on Voyage and a subform based on CrewList with a combobox based on Crew
There are a number of refinements you could add.
Make sure you do not use reserved words like Name and do not put spaces in field names. You will thank yourself later.
See also create form to add records in multiple tables
I'm struggling to decide what database schema to use. One large table, or many small (though more difficult to manage).
I have 10 templates each with their own text fields. I am trying to store the text for the templates in a database and then when the web page is called I will show the correct text in the html template. Because a mixture of these templates are to be in a sequence of screens where you can navigate backwards or forwards, I need to be able to sequence them, I can only think of adding a page_number column. I also would like to re-order them and delete them as necessary using the page_number column.
I was planning to do all this in a web application without the need for a standard folder/web page structure, like a small CMS system.
option 1,
I can create one large table with many columns, lot's of which will be empty, over half with each row. Is this bad?
option 2,
I could create many tables using only the relevant template columns required.
The problem I see with this, is the headache of repopulating a column in each table when I delete a row, because I need to re-sequence a column that represents page numbers. Which I reduce if I use one large table.
I've thought of moving page numbers into another table called page_order but I cannot think of a way to maintain an effective relationship between the other tables if I make changes.
I'm yet to figure out how to re-sequence a column in a database when a row is deleted. Surely this is a common problem!?
Thanks for taking the time to help!
Have one table that contains one row per template. It might look like:
id (INT, auto-increment)
page_order (INT, unique key here, so pages cannot have the same number)
field1 (STRING, name of the text field)
value1 (STRING, contents of the text field)
field2
value2
Then you have to decide the maximum fields that any page can have (N) and keep adding field/value columns up to N.
The advantage of this is you have one table that isn't sparsely populated (as long as the templates have about the same number of fields, even if the names of those fields are different).
If you want to make an improvement to his (maybe not necessary for a small amount of data) you could change field to an INT id and connect it to a lookup table that contains (field_id, field_name).
Im using Asp.net (VB.net), in my Database :
have One table called (Trade), the same rows of this table are used from 3 different users, These users can make different updates on this table, they should see the basic informations of the table (I mean by the Basic, before the table (trade) has been updated)
The problem is here when the first user wants to modify the table's rows, the second and third user cannot see the basic information any more, and if they decide to change or update some data, the first will lose his updated rows..
The data will be overwritten every time the users make updates on the table.
What I want, is to know if there is a way to do like a copy, or an image of the table for the 3 users, and every user can update normally, without creating the same Table with the same rows 3 times??!
Update
My table structure is: Trade(trName, Carrier, POl, POD, Vgp, Qgp) There is no primary key..
Thank you..
Solution to your problem could be two copies of the original table. Show the original table always to the user as the initial data. And in second table keep the updated data always. Now the trick comes here to maintain the log, for that you have to maintain the log table, this table will have all the fields of original table along with one additional column "UserId", this will have the ID of user who has changed the value. Now each time before updating the data, copy it in the log table. If this suits your need then post the fields of your table then we can workout on the table structures.
I know this has been asked before..sort of. And that's why I'm posting. Basically I'm building a report in Crystal that relies, to keep this simple, at least 3 tables.
Table A is inner joined to table B by a unique ID. Table B has a child table that may or may not have data related to this unqiue ID.
As a general example table A is a customer table, table B is a product table and the child table is contains the product number. All customers have a product, but not all customers have product number in the child table. I hope I've explained that simply enough.
My issue is sort of between Crytal and Access and how to query this. When I'm writing behind something in VB it's easy enough to write and execute a query and display the result in the desired manner. However I can't seem to get my query straight... I either end up with a report with cartesian product as the resultset, which displays ok...except that even with the few records I have ends up being about 30k pages..or I end up with a blank dataset because the child table does not have corrisponding data to B.
Using outter joins I've managed to get my results within some amount of reason but not acceptable to a real world report. I'm sure this issue has come up but I can't seem to find any suitable answers and to be honest I'm not even sure what questions to ask being a Crystal n00b.
What I'm really after is the data from Table A, the data from Table B and children tables. While they are logically linked and can be linked with the ID field, it isn't necessary I don't think because I am taking a parameter value for the report of the ID field. And once the tables are filtered, no other action needs to be taken except to dump them back on the report.
So can anybody point me in the right direction? Can I set up individual datasoruces (unrelated) based perhaps in a seperate section? Should I build a tree of queries and logic in my DB to get what I need out? I've been racking my brain and can't seem to find the right solution, any and all advice is apreciated and if I can clarify anything or answer any questions I will.
Thanks in advance.
As per requested below:
Section1
ID fname lname
01 john smith
Section2
ID notifiedDate notifiedTime
01 10/10/2012 12:35PM
S2childAdmin
ID noteName
01 jane doe
This data is logically related and can be related in the DB. However it is not necessary as long as the ID parameter is passed to each table. Querying Section1 inner joined with Section2 works fine. But any other arrangements result in more rows than required and I end up with a report many times duplicated. What I really need is something like Section1 joined with Section2 and S2childAdmin as a freely availble table. Otherwise it multiplies my data or results in a null recordset (because it can return 0 rows)
I think this should help point you in the right direction, though it has been 5 years or so since I did heavy Crystal Reports work.
One option might be to join everything using Outer Joins like you stated you were, then use a Crystal Report 'group' on the Table A ID, with a group based upon Table B ID inside of that. So you would, in the actual 'Detail' area put your table C details if there were any, and then use the Group header/footer for Table A and Table B to show data specific to those objects.
Another possible solution that may fall short of your requirements but might get you thinking in another way, is to create your main report and in it, display the fields from table A. Then below those fields include a sub-report and pass in the unique ID from Table A. You will then have a query inside of the subreport that finds all of the Table B records with that Table A.ID value and displays their details.
At this point you run into a weakness of Crystal Reports (at least as of the last version I used) in that you cannot have a subreport inside of a subreport.