I have a table where a customer can define different Levers
CF_LEVER
I want to give customer an ability to store any combination of these levers for example
FYI - Lever_Name and Lever_Value shown below is for clarity [it will be replaced by Lever_Id[PK of CF_Lever] in table design]
My question is about this Lever_Combo_Id [it signifies what levers combinations are created]. For example in the screenshot above, we created a combination [Lever_Combo_Id] for Product = ABC, SalesChannel = Phone and CampaignId = 4325234. There could be thousands of these combination. Is there a better way to design this table, rather then maintaining a LEVER_COMBO_ID key at application Level.
Related
Using Java and Oracle.
We need to update changes in Email, UserID of employee to third party.
Actual table is Employee and intermediate table we keep which we will use for comparison of changes before sending to third party.
Following are database designs coming in mind for intermediate table:
Only Single table:
EmployeeiD|Value|Type|UpdateDate
Value is userid or email, type will be 'email' or 'userid'. Update date is kept so to figure out that which of email or userid was different and update to third party.
Multiple Table:
Employee_EmailID
EmpId|EmailID|Updatedate
Employee_UserID
EmpId|UserID|Updatedate
Java flow will be:
Pick employee from actual table.
Pick employee from above intermediate table.
Compare differences. Update difference to third party.
Update above table with updated value and last update date.
Which one is consider as best way, single table approach or multiple table or is there any standard way to implement the same? There are 10,000 Employees in system.
Intermediate table is just storing Delta records i.e Records transferred to third party so that it can be compared next day.
Good database design has separate tables for different concepts. Using the same database column to hold different types of data will lead to code which is harder to understand, prone to data corruption and less performative.
You may think it's only two tables and a few tens of thousands of rows, so does it matter? But that is only your current requirement. What you choose now will set the template for what happens when (say) you need to add telephone numbers to the process.
Now in future if we get 5 more entities to update
Do you mean "entities", like say Customers rather than Employees? Or do you really mean "attributes" as in my example of Employee Telephone Number?
Generally speaking we have a separate table for distinct entities, and all the attributes of that entity are grouped at the same cardinality. To take your example, I would expect an Employee to have one UserID and one Email Address so I would design the table like this:
Employee_audit
EmpId|UserID|EmailID|Updatedate
That is, I have one record which stores the complete state of the Employee record at the Updatedate.
If we add a new entity, Customers then we have a new table. Simple. But a new attribute like Employee Phone Number offers a choice, because an employee can have more than one: work landline, mobile, fax, home, etc. So we could represent this in three ways: a child table with a type column, multiple child tables for each type, or as distinct columns on the Employee record.
For the main Employee table I would choose the separate table (or tables, depending on whether I'm shooting for 6NF). But for an audit table I would choose one record per Employee and pivot the phone numbers like this:
Employee_audit
EmpId|UserID|EmailID|Landline|Mobile|Fax|Home|Updatedate
The one thing I would never do is have a single table with type and value columns. It seems attractive because it means we could track additional entities without any further DDL. But in fact it becomes harder to re-assemble the complete state of an Employee at any given time with each attribute we add. Also it means the auditing process itself is more complicated (because it needs to determine which attributes have changed and whether it needs to audit the change) and more expensive (because changing three attributes on the same record entails inserting three audit records).
I am trying to set up multiplier in one of the forms. I have followed all the articles and I think I have the setting right regarding multiplier content. Now I need help with setting up two tables to save the data.
My first table will have all the fields and a foreign key which will point to multiplier data.
Form design:
Setup:
Your first table can be set up using the settings in the ChronoForms Create Table dialogue, but you should leave out the columns for the three multiplier elements.
The second table needs to have columns for an auto-incremented primary key plus a column for the record id from the first table plus the three multiplier elements. You could create this from the Create Table dialogue by manually editing the settings, or, if you prefer, you can use PHPMySQL or some similar database editor.
Bob
I have looked for an answer here among other places but havent quite been able to find what I need to know.
I have 3 tables, Order_Details, Products_Ordered and Product_Details. The first two are being used in a master detail form to show the order and the items ordered together. The Products_Ordered table has a composite primary key made from two foreign keys, the first being the primary key from the Order_Details table, and the second being the primary key from the Product_Details table. Together they ensure that a type of product can only be added to an order once. If someone wants to order more than one product then the quantity field in the record can be altered to reflect this. All that seems fine so far.
My issue is that when adding products to the order in the master detail form i have used a drop down list of values to select the product to add to the order. the display value for this is the product name and the return value for it is the primary key for the product from the Product_Details table.
I like this because its easier for the user to simply select the product and add a quantity of it to the table. And it works fine for both insert and update operations apart from one situation.
If the user selects the same product in to rows then submits the table the database then tries to add the product to the order twice, throwing a "ORA-00001: unique constraint violated." error. Obviously this is because of the product ID being used in the primary key of the table.
I don't want to allow the user to add two records to the table like that, rather id like to force them to alter the quantity field accordingly. The error message that comes up isn't very user friendly so my question is how can I detect this error and display a more user friendly one instead telling them to alter the quantity field instead?
*If this isn't possible then is there a way that I can hide any already selected products from the dropdown list of values in the following table rows? I haven't looked into this too much because surely it would get complicated when the user tries to add more rows than products available in the dropdown and there are no more products values to show?
I am quite new to this so please be nice. Any help is greatly appreciated :D
Here is a link where all is nicely described:
https://docs.oracle.com/cd/A97630_01/appdev.920/a96624/07_errs.htm
Section
Predefined PL/SQL Exceptions
in combination with:
Defining Your Own PL/SQL Exceptions
and
Defining Your Own Error Messages: Procedure RAISE_APPLICATION_ERROR
Hope it helps...
I have to design data warehouse model and ETL process for class at my University. My data warehouse has to store opinions / comments about a product, each record should consist of:
comment text (String)
product score ({0, 0.5, … , 4.5, 5})
comment author (String)
comment date (Date)
product recommendation ({Yes, No})
comment up votes (Int)
comment down votes (Int)
product pros (many Strings, e.g {price, design, durability, … }) and its count
product cons (many Strings, e.g {too loud, too heavy, price, … }) and
its count
In addition data warehouse should store information about product:
product category
product brand
product model
I want to create data warehouse model first, but I have problem with storing product pros and cons as it is many-to-many relationship. In normal relational database I would simply create associative table, but here I am not sure how to proceed, after all I don’t want to normalize facts table.
I am considering 3 approaches, first, which I presented in diagram below. I used bridge table method (though, I don’t know if correctly) to get rid of many-to-many relationship. I don’t know how it will impact querying performance.
Second approach I may use is boolean column method. In PROS and CONS table I can create a column for each possible value, but there can be up to 100 different pros or cons. Also number of possible pros or cons is not constant in time. Authors in their comments can list new pros or cons (that’s how it works in data source), but I can’t add new columns (I shouldn’t change data in data warehouse).
Third approach I am considering, is to keep pros in PROS table but in 1 column, where values will be separated using commas or some other delimiter e.g. “price, design, color”. It keeps things simple but hard to analyze or slice & dice.
Which approach should I use in this situation? Which is better for loading data into data warehouse, because form data source I will get all the comments and I want to only load comments that are new since last loading?
What I think is, if we can get your first option little bit modified to than what you have said here, it would be the best as I understand.
in your image you have provided, having the Pros_Bridge_Detail table is fine. The rest need to be changed.
you can remove the pros_Bridge table that holds just the count. you can actually add that column to your COMMENT fact table you have up there. That would be more efficient and easy when it comes to queries rather than querying in many tables.
you said you have many areas to give pros like price, design, durability etc. Lets put those stuff into a separate dimension.
Add a new column to your Pros_Bridge_Detail table to hold the ID of the newly created Dimension that holds the product pro types (Design, durability etc).
Now, once you add a product Pro, the Pros_Bridge_Detail table will have the pros the user give and also hold the value of regarding what the pro is given via the ID of the new dimension.
Also don't forget to store the Comment ID as well in Pros_Bridge_Detail table as that will be your link (FK) to Comments fact table you have.
Same can be done to Cons as well.
Hope you understand what I just explained and hope it helps. let know if you have any issues.
https://web.stanford.edu/dept/itss/docs/oracle/10g/olap.101/b10333/globdiag.gif
Assume that we have a start schema as above..
My questions is - In real-time how do we populate the colums (unit_price, unit_cost) columns of the fact table..?
Can anyone provide me a start schema tables with real data?
I am having hard time in understanding star schema...
Please help!..
Start schema consists of two types of tables fact tables and dimensions.
The ideal of the star design is that you can split your data in two part.
The static part is described with dimensions and the dynamic part (= transactions) in the fact table.
Each transaction is stored in the fact table as a new record and is connected to the surrounding dimensions, that define the context of the transaction.
The example in link contains two fact tables: SHIPMENTS and PRODUCT_CONDITIONS.
Note that the fact tables in the link are dubbed UNITS_HISTORY_FACT and PRICE_AND_COST_HISTORY_FACT, but I find this not a best choice.
The SHIPMENTS table stores one record for each shipment of a PRODUCT to a CUSTOMER at some TIME, via a defined CHANNEL.
All the above information is defined using the corresponding keys of the respective dimensions.
The fact table also contains MEASURES describing the attributes of the transaction, here the number of UNITS shipped.
The structure of the fact table would be therefore
CUSTOMER_ID
PRODUCT_ID
TIME_ID
CHANNEL_ID
UNITS
The second fact table (bottom) is more interesting, because here you split the product in two parts:
PRODUCT dimension defining the ID, name and other more static attributes
PRODUCT_CONDITION this is fact table, designed with the expectation the price and cost of the product will change over time.
With each change of the price or cost insert a new record in the fact table and connect it to the PRODUCT and TIME (of change).
The structure of the fact table would be therefore
PRODUCT_ID
TIME_ID
UNIT_PRICE
UNIT_COST
Final note the the design of the TIME dimension.
The best practice to connect the fact table with the dimension tables is to use meaningless ID (surrogate keys), but for TIME dimension you should be careful. For big (time partitioned) fact table is often used the natural key (DATE format) to be able to deploy the partitioning features. See more details in How I Defined a Time Dimension Using a Surrogate Key and other resources in web.