Hi,
A Composite entity can be made out of two Primary Keys (PK) of two different entities. Therefore it can be called as a link table. Therefore the composite entity depends upon the other two entites. Therefore the composite entity is a exsitence dependent on the other two entities.
Therefore do every composite is a weak entity?
TY
Apologies if this has already been asked and answered, though I haven't found it via search.
In my report model I have a lookup entity that consists of a Code field (PK) and a Description field this is linked to a parent entity (table) and works fine, e.g. the description is shown in the parent entity instead of the FK code. However this lookup entity would be useful linked to many other entities (tables) which use the same FK code linked to the lookup entity's Code field (PK) for use of the Description field. In my first attempt I linked the lookup to a second table entity but unlike the originally linked table entity, this is not shown as the description in report builder, only the role appears and I have to select the role then the description from the 2 fields displayed (Code, Description), additionally I get shown the related first table entity.
Firstly can a lookup entity be linked to multiple tables?
Secondly, if so am I forgetting something so only the description is shown like in the first linked table entity?
Thirdly, if I correct the problem is there a property I need to enable/disable to stop the first linked table entity appearing in the second table entity entity list in report builder or should I just leave it?
Any help/advice/suggestions would be appreciated, and apologies for long list of questions but all the books and help files I have used don't seem to use imperfect/real life data sources and examples.
Thanks
Andy
Hello,
I have a table which has a composite primary key consisting of four columns, one of them being a datetime called Day.
The nice thing afaik with this composite key is that it prevents duplicate entries in the table for any given day. But the problem is probably two-fold
1. multiple columns need to be used for joins and I think this might degrade performance?
2. in client applications such as asp.net these primary keys must be sent in the query string and the query string becomes long and a little bit unmanagable.
A possible solutions I'm thinking of is dropping the existing primary key and creating a new identity column and a composite unique index on the columns from the existing composite key.
I would like to have some tips, recommendations and alternatives for what I should do in this case.
plzzzzzzzzzzzzzzzzzzzzz !!!!!!!
help i m new to SQL and weak at making queries
can u please suggest me some books or site from
where i can pratice making queries
u can mail me at
rastogi.akash@gmail.com
Greetings everybody,
lately we are experiencing some very strange behaviour on the part of our
SQL-Server.
We are using SQL-Server as a combined Database for one COM+ application and one J2EE-Application. All of this is installed on the same machine (dual-CPU, 2 GB RAM).
This setup has been up and running for almost a year now.
In the last two weeks there have been incidences where the performance of SQL-Server is decreasing steadily until it finally hangs completely (just SQL-Server, not the machine itself).
This happens 2-3 times a week, curiously always between 9 and 10 a.m.!
After stopping and restarting the actual SQL-Server "Service", everything is back to normal (until the next morning or the morning after that).
There are a few automated batches that access the database via the COM+ Server. These run at night and are completed before work begins at ca. 7 a.m.
Profiler-Logs show a few "Escalate Locks", but those alone cannot account for this strange behaviour.
Any help or info would be greatly appreciated.
Hi,
I’ve three questions, would someone answer them please,
I have 3 entities:
The book entity(BookNo,BookNmae,AuthorName,Price...etc), the MembershipCard entity(CardNo,MembershipNo,ClientNo,PublishDate,EmpNo..etc), and the Client entity(ClientNo,ClientName,ClientAddr,ClientPhoneBookNo,RequiredBookNo,..etc)
1-What is the relationship degree between them, is it ternary or binary?and Why?
I'm so confused ,my answer is ternary, I made a (1:m) relationship between the clients entity and the books entity (a client may buy more than one book), (1:m) relationship between the employee entity and the books entity (an employee may sell more than one book)and a (1:m) relationship between the employee and the Client(an employee may serve more than one client(is it right or it's (M:N)).
So is my answer is right or wrong, please help me to understand, I’m so confused.
2- Is the cardinality degree between the Client entity and the book entity , (0,N) for the client entity and (1:N) for the book entity??
3-What is the best model to use in designing data in general,Chen's model or Crow's Foot and why?I think it's Crow's one ,for it's more arranged and easy to read.
with thanks
deema
I created a report model with a single "data source view." The datasource view has three tables "Business, XRef, Employee" and a named query "PeopleCount" based on these tables. The smdl [design] view shows "Business, XRef,Employee" as "entities" and does not show the named query from the "data source view" (I don't know if that is normal). I published this report model to the reporting server (its showed "success").
I then used Report Builder to open the report model as a "chart", and it shows there is only one entity for me to play with, its called "XRef." Why do the other tables ("Business" and "Employee") not show up in the Report Builder's list of entities?
My own guess is that "XRef" is the only "actionable" table for making a chart. Indeed, I notice that among its "fields" is one called "Business Title" (which apparently comes from the Business table). But I also notice it does not have an "Employee Name." Why have the former and not the latter? Again, my own guess is that the type of the Employee.Name field, a nvarchar(MAX), might be considered unusable for reporting, since it is a "max" size. Thoughts?
I am using SQL Server 2005 RTM, which is running on Win 2K3 Server SP1.
Why is it that only SOME of the tables in my database show up in the Entities pane?
There are a total of six tables in my database, yet only three of them are available to me in the Entities pane. I have looked at permissions, etc, and I am using the SA account. It seems like I should see either ALL or NONE of the tables, but that is not the case.
What am I missing?
I have to connect 6 entities. I am getting NO RESULT (no output)!!!
BEGIN TRANSACTION;
DROP TABLE TOPIC;
DROP TABLE LECTURE;
DROP TABLE PRICE;
DROP TABLE COURSE;
DROP TABLE PUPIL;
DROP TABLE LP;
[Code] ....
Dear GroupCan anyone provide a sample query for the following scenario?Let's assume I want to search for an order someone placed which mightbe an individual or company. An individuals first name is stored incolumn FirstName And the individuls last name in column LastName of thecontact table and the company name is stored in column CompanyName ofthe company table.If a user issues a query with CName parameter how can I search allthese columns and tables at the same time to see if there's a match? Imight add that there's a column in the orders table that holds0=Contact 1=Company but ideally I don't want to use this column.Thanks very much for your help and efforts.Martin
View 2 Replies View RelatedHi Everyone,
I'm attempting to design a schema for a project I working on. The idea is that I can store a list of documents and associate meta data with them.
The problem is that I don't know what that meta data will be at design time. The user will create the meta data fields in the software. For the first design I just had a table called meta field that contained the meta field defintion, and another table called itemdata that contained the document primary key, the metafield primary key and a value encoded as a varchar. This works fine while the list of documents is small.
Another idea I've thought of is to have seperate tables for all of the metafields. This would allow me to be very specific about the values that can be stored in that column etc. It also turns out that for the kind of queries I'm doing its about 4 times as fast. The only problem is that the software will need to create these tables at run time.
What I would like to know is, is this a really bad idea? If so why?. Also are there any other ways I can store this kind of data?
The kind of queries I am doing are find all the documents where metafield 1 is A and metafield 2 is B and metafield 3 is C and metafield 4 is D etc.
Cheers,
Mark
Our customer (of our ecommerce system) wants to be able to preservedeleted entities in the database so that they can do reporting,auditing etc.The system is quite complex where each end user can belong to multipleinstitutional affiliations (which can purchase on behalf of the user).The end user also has a rich trail of past transactions affiliationsetc. Thus in the schema each user entity is related to many otherswhich in turn relate to yet others and so on.In the past when a user was deleted all of his complex relationshipswere also deleted in a cascading fashion. But now the customer wantsus to add a "deleted" flag to each user so that a user is never_really_ deleted but instead his "deleted" flag is set to true. Thesystem subsequently behaves as if the user did not exist but thecustomer can still do reports on deleted users.I pointed out that it is not as simple as that because the user entityis related to many, many others so we would have to add this "deleted"flag to every relationship and every other entity and thus have"deleted" past purchases, "deleted" affiliations - a whole shadowschema full of such ghost entities. This would overtime degradeperformance since now each query in the system has to add a clause:"where deleted = 0".I assume this is a standard problem since many organizations must havethis need of preserving deleted records (for legal or other reasons).I tried to talk them into creating a simple audit file where all thedeletions will be recorded in XML but they were not too happy withthat.Is there a more satisfying solution to this than have this "deleted"flag?Thanks for your help,- robert
View 9 Replies View RelatedHi everybody,
When I've deployed a report model,in Report Builder I have 4 different entities at the same level,when I drag and drop the first field from one entity after I can't see the other three entities....What did I do wrong??
I don't understand ,if you could help me it would be great.
Have a nice day!
sandy
I have the following data stored in a column in a table:
£10,000.00 & ' " % < > Guðmundsdóttir Björk Lårs Marqués María-Jose Carreño Quiñones
I query this in a stored procedure using the FOR XML clause and universal table, and store the result in an XML data type variable:
DECLARE@ResultXML
EXECUTE[someStoredProcedure] @Result OUTPUT
This data (as XML) is then written to a file; in order to do this, I CONVERT the data to NVARCHAR since there are unicode characters in the source:
DECLARE@strResultNVARCHAR(MAX)
SET@strResult= CONVERT( NVARCHAR( MAX ), @Result, 1 )
Now this works fine, except on inspection, SQLServer has decided to render the data thus:
£10,000.00 & ' " % < > Guðmundsdóttir Björk Lårs Marqués María-Jose Carreño Quiñones
Why it has changed the apos and quot entities to the corresponding character but not the other entities is beyond me.
how to preserve XML entities?
I have a database that tracks players for children's sports clubs. I haveincluded representative DDL for this database at the end of this post.A single instance of this database supports multiple clubs. I would like toadd support for letting each club define and store custom information aboutarbitrary entities. Basically, allows the clubs to define custom entities(i.e tables) and associated custom attributes (i.e. fields) that may berelated to existing tables (such as Player and FootballClub) or existingentities. For instance, a club may define a PlayerAssessment entity thatrecords all player assessments.To do this, I plan to support the following use case:1. FootballClub admin creates a new entity and gives it a name anddescription (Entity is only accessible to this FootballClub).2. FootballClub admin indicates that the new entity has a M:1 relationshipwith the Player table (this will add Player_ID as a FK attribute).- {An entity may have no relationships.}- {Relationships are also supported to other entities.}3. FootballClub admin specifies the names and domain/types of any dataattributes (i.e. fields) of the entity.- {An attribute's type may be constrained to a few allowable types likeRelationship, Integer, Float, Currency, Date, Time, DateTime, Name,Description and Memo.}4. System creates entity as specified.A few constraints:1. Any entity defined is "private" to the defining club. Other clubs aren'taware of it although they may define custom entities of their ownwith the same name and attributes. [Perhaps there is a way to sharedefinitions of identical entities?]2. A club doesn't have to define any custom entities.Ideas I've considered:1. Generate DLL and create actual tables- Restrict such customizations such that while admin is setting up entities,no other user is allowed to use the system.- Once entity definition is complete, generate an actual table using DLL.Table and column names might be changed to enforce uniqueness/validityconstraints - this suggests a need for table/column name mapping.- PROS: Easy to implement.- CONS: Doesn't scale since only a limited number of tables can be created.DDL on a live, shared system?. Scary!!All users for all clubs will be locked out while entity iscreated.2. Generate DDL and create actual tables in secondary database(s)- Same as above except that the user tables are created in secondary [,shared] databases.- PROS: Reassurance that DDL is never run on the "core" dataAll users don't have to be locked out.- CONS: Doesn't scale since only a limited number of tables can be created.{ Unless I start creating additional databases too!. }Still needs to DDL on a live, shared system.Has anyone done anything similar?. Any ideas on how it might be done?. Inparticular, is this possible without having to execute DDL on the livedatabase?Kunle=================== BEGIN DDL ===================CREATE TABLE FootballClub (Club_ID int IDENTITY,Name char(80) NOT NULL,Area char(4) NOT NULL,League char(4) NOT NULL,City char(30) NOT NULL,PRIMARY KEY (Club_ID))goexec sp_primarykey FootballClub,Club_IDgoCREATE TABLE Player (Player_ID int IDENTITY,First_Name char(30) NOT NULL,Initials char(30) NULL,Last_Name char(30) NOT NULL,Date_Of_Birth datetime NOT NULL,Position char(4) NULL,Club_ID int NULL,PRIMARY KEY (Player_ID),FOREIGN KEY (Club_ID)REFERENCES FootballClub)goexec sp_primarykey Player,Player_IDgoCREATE TABLE UserAccount (User_ID int IDENTITY,Club_ID int NOT NULL,FullName char(80) NOT NULL,Logon char(20) NOT NULL,PWD_Hash char(60) NOT NULL,PRIMARY KEY (User_ID, Club_ID),FOREIGN KEY (Club_ID)REFERENCES FootballClub)goexec sp_primarykey UserAccount,User_ID,Club_IDgoexec sp_foreignkey Player, FootballClub,Club_IDgoexec sp_foreignkey UserAccount, FootballClub,Club_IDgo=================== END DDL ===================
View 3 Replies View RelatedQuestion is in the subject.
Thanks in advance
-Jamie
I have configured master data services in my DB server and when i am going to explorer the entities and respected data by using navigating as below
[URL] -->Click to Explorer
I am able to select data for only one default entity, in entities drop down is getting hidden back side , please find below snap to clearance.
Note: I am using Internet explorer (11.0.9600.17239) to browse the solution.
I have scoured the internet looking for someone who has run into this issue with no such luck!
Product: Reporting Services 2005 Analysis Services 2005
Our users use Report Builder as an ad-hoc report tool. Data sources for Report Builder come from Report Servers and Analysis Servers.
I have run into issues where a user will select a source for their report that is based on an AS cube. When they select an attribute (field) from a selected entity in the Report Builder Explorer and drop it on the canvas, all entities except the one the field was selected from disappear.
For example:
A cube has a fact table called "Annual Income" with dimension of employee and demographics. In Report Builder, the entities would be listed in the left hand Report Builder Explorer window as
Annual Income
Employee
Demographics
If I select attributes from Employee or Annual Income, as usual, you will see the related hierarchies of the remaining entities. However, if I select an attribute from Demographics, then the Annual Income and Employee entities just disappear and all I can see is the Demographics entity and its attributes.
Has anyone run into this and if so, any ideas? This is becoming extremely frustrating. I have deleted and rebuild cubes, individual dimensions, and everything else I can think of.
Your responses are appreciated,
Scott
Let's say I have an rdlc report for customers, and it has three sections with subreports:
CUSTOMER_INFO (name, phone, e-mail)
ITEMS
OBSERVATIONS
As the page only has 21cm and the report grows horizontally, I need to repeat the WHOLE report with all of its sections after every 4 customers. So if I have 5 customers, there would be three pages(let's say every subreport takes 1 page) for the first four customers, and then another three pages(with every section once again) just for one customer.
Is it possible? It doesn't seem somehing out of the ordinary, but I can't figure how to make it work. Everytime there is more than 4 customers, the report breaks its layout trying to accommodate the records in a new table below the tables of each subreport.
The expected result would be to bring all of exceeding data to new pages.
I am trying the assign the models to the user in the user management page. But when I try to expand the + symbol next to the model and open the entities, I get the error that the object reference is not set for a object server instance.
View 2 Replies View RelatedI'm just now learning both SQL and ASP.NET, and I cannot seem to figure out how to build my data structure. I believe the answer to my problem is a composite key, but I cannot seem to get it to work. Here is an example. My database is of recorded dances, with exact locations within a ballroom. I believe I need 2 tablesTable #1 - DanceTableColumns: DanceID, Name, Description, TagsTable #2 - StepsTableColumns DanceID, StepID, longLocation, latLocation, Action, DescriptionWithin my ASP.NET application I want to be able to enter data about a dance, including metadata and a series of steps. The Dance and metadata content to be stored in DanceTable, and the series of moves stored in the StepsTable. I want the steps to be IDed as 1, 2, 3, 4...x with the first step being labled 1. and I want each dance to have it's own unique ID (DanceID). Right now I'm using "ExecuteNonQuery()" to add my data to my SQL database, and when I add new steps to the StepsTable SQL just finds the largest ID within StepID and increments it by one. So my steps are labeled as:Dance1:Step1, Step2, Step3, Step4Dance2:Step5, Step 6, Step7What I really want is (or I think what I want is) is a composite primary key.Dance1:Step1, Step2, Step3, Step4Dance2:Step1, Step2, Step3That way the StepID is used as both a primary key and it indicates the position within the dance. I guess I could just use a standard SQL table, let SQL auto generate StepID's and then add a new column called something like "StepNumber", but it just seems goofy to be generating a stepID and never using it. With composite keys (If I understand them) each step would have a unique key as a combination of the DanceID+StepID (AKA Dance 345, steps 1-10). I pull up data by searching for dances, and then sort by StepNumber, and those should all be unique...if I can figure out how to build them.
View 1 Replies View RelatedI have a table with a composite key formed by the unique combination of columns w, x, y, z
I'm trying to write an INSERT statement along the following lines
INSERT INTO myTable
(SELECT w, x, y, z FROM someTable) t1
WHERE (this is the part I'm stumped on - where the unique combination of w, x, y, z is NOT in myTable already)
Help would be appreciated. Can you use the NOT IN keyword on composite values?
How can I create a composite key (two primary keys for one table) using SQL Server 2005 Management Studio? Can I do it using the GUI, or do I have to write SQL code to do this? Thanks
View 7 Replies View RelatedMade an interesting discovery today - a column of data type Bit is not allowed to participate in composite key. Rather surprised.
I have a certain unique code that exhibits 2 unique states, which rendered the use of the boolean column, so the uniqueness goes <code>-1 and <code>-0. Is there any 'hack' so to speak to avoid using a Tinyint for the boolean column instead?
Hi,
Suppose there is a composite index on a table, and in includes, for example 3 columns.
If I do a select using one of those three columns, will the select use the composite index? Will it aid in retrevial or should I create an index on the
individual column.
any thoughts on this would be appreciated.
thanks
Can someone help me create a composite key on ms sql server through the enterprise manager?
Thanks,
Laura
The orininal design of my db (part of it...) is the following
A JOB has a Number and a Description.
Each JOB can have one or two TASKS (min one, max two). Each TASK is identified by the JOB it belongs to and an Index (unique only for the same JOB).
Each TASK has one an only one set of INFO1, one and only one set of INFO2, one and only one set of INFO3 etc.
A: JOB (JobNum [PK], JobDescription, ...)
B: TASK (JobNum [PK] [FKa], Index [PK], TaskDescription, ...)
C: INFO1 (JobNum [PK] [FKb], Index [PK] [FKb], ...)
D: INFO2 (JobNum [PK] [FKb], Index [PK] [FKb], ...)
(There is a reason to keep INFO1, 2 and 3 separate, because eachof them will be linked to different table. This might influence the answer to my real question.)
First of all, I wouldn't add any surrogate key for TASK, not to loose the logic behind; plus I'd put an ined on JonMum only, being Index equal to 1 or 2 only, so not selective.
The real question is about INFO1 (and 2, 3 etc.) table: should I leave JobNum and Index as PK (consider that the PK of INFo1 will be used as FK for another table), or should I use a surrogate key, like for eaxmple
C: INFO1 (Info1ID [PK], JobNum [FKb], Index [FKb], ...)
I don't really like this solution. Actually I'd prefer the following
C: INFO1 (Info1ID [PK], ...)
where Info1ID = JobNum + Index (+ = string concatenation).
Any suggestion?
Thanks
Hi folks, i need an advise.
I've a gerand table customers_orders table with customer_id and order_id.
Whenever we have to find orders, for customer, this table is involved. Hey; i know u'll be angry y the heck this gerand exist but i've to blame the older dudes then.
Now this table has composite clustered index; CUSTOMER_ID+ORDER_ID.
The tables have grown over GB size; i see HASH INNER JOIN rather than MERGE for the GEREND and CUSTOMER table join.
Is it good to use composite clustered index; or should i clustered one the columns in the GEREND and other to normal index. What performance impact it could be.
Howdy!
WHile designing a Database should one go for composite Primary Keys.
Or what are the Pros and Corns of Composite Primary Keys
Thanx
Hello, everyone:
I need to define composite PK and FK for a ERD. Could someone offer the methods that work with,
1. T-SQL
2. ERD
Thanks a lot.
ZYT
I've been facing this situation since long but today i am asking here. Suppose i have a following tables;
AdmissionInfo, AdmID, AdmDate, AdmFee etc.
SubjectInfo i.e. SubID, SubName, SubStatus etc.
The Result table is like this:
ResID, AdmID, SubID, TheoryMarks, PracticalMarks, ObtMarks, TotalMarks, ResultTerm, SubPercentage.
ResID is PK, AdmID and SubID are Foreign Keys, right. Now What i want to ask/ learn that Am i suppose to combine ResID, AdmID and SubID as a composite PK or should i simply make the ResID as PK and other 2 be there as FK? When do we really need to use Composite PK and using it a good thing or not?
i have a master table with around 15 columns and i am trying to findthe appropriate primary keys and indexes for the table.To make the records unique, i need to include two datetime columns (start and end dates ) and two integer columns ( attributes of therecord ) to make up a composite primary key. Both of these fourcolumns are found in the WHERE clause of my queries.Is it acceptable in the view of performance and how should i createthe indexes?
View 5 Replies View RelatedThis is really not a T_SQL question but there's no good category for it so I thought I'd just put it here.
I have a table that will contain a large amoutn of data in one field, and every piece of this data is uniquely identitied by six other attributes, that is, six other fields (e.g. user_ID, type_ID, year, country, state, item_ID). I can either make these six fields into a composite primary key, or add an additonal field (say an identity column) as the primary key and add a unique constraint on these six fields. What are the pros and cons of both designs? The one data field is of nvarchar(2000) type and the table is likely to have 50 million+ rows in a couple of years of real use.
This table is not referenced by any other tables so whatever the primary key is, there's no FK reference. However, there could be FK references to this table in the future. Does the FK possibility make a difference in the design considerations?