Table Names As Keys?
Jul 20, 2005
Hello all,
I got a chance to peak into a database system. Part of its design is
rather unfamiliar to me. When I look at the diagram generated by SQL
Server, there are many floating tables. Eventually it turns out that
these many floating tables are actually not floating. Their table
names relate to fields (as TableID) in other tables. In this case,
you can get a handle to one of such tables by search TableID columns
in other tables.
To be more specific, the database is a microarray database implemented
in SQL Server 2000. They have a table called MICROARRAYS. In this
table, there is a column called table_id. These table_ids are in fact
table names of a bunch of other tables.
My questions are
1) Is this good relational design?
2) How well is this kind of design supported in SQL Server?
3) Are there better alternatives?
Any other comment or link to helpful resources will also be
appreciated.
Thanks,
Eric Wu
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Apr 11, 2006
Hello again,
I'm going through my tables and rewriting them so that I can create relationship-based constraints and create foreign keys among my tables. I didn't have a problem with a few of the tables but I seem to have come across a slightly confusing hiccup.
Here's the query for my Classes table:
Code:
CREATE TABLE Classes
(
class_id
INT
IDENTITY
PRIMARY KEY
NOT NULL,
teacher_id
INT
NOT NULL,
class_title
VARCHAR(50)
NOT NULL,
class_grade
SMALLINT
NOT NULL
DEFAULT 6,
class_tardies
SMALLINT
NOT NULL
DEFAULT 0,
class_absences
SMALLINT
NOT NULL
DEFAULT 0,
CONSTRAINT Teacher_instructs_ClassFKIndex1 FOREIGN KEY (teacher_id)
REFERENCES Users (user_id)
)
This statement runs without problems and I Create the relationship with my Users table just fine, having renamed it to teacher_id. I have a 1:n relationship between users and tables AND an n:m relationship because a user can be a student or a teacher, the difference is one field, user_type, which denotes what type of user a person is. In any case, the relationship that's 1:n from users to classes is that of the teacher instructing the class. The problem exists when I run my query for the intermediary table between the class and the gradebook:
Code:
CREATE TABLE Classes_have_Grades
(
class_id
INT
PRIMARY KEY
NOT NULL,
teacher_id
INT
NOT NULL,
grade_id
INT
NOT NULL,
CONSTRAINT Grades_for_ClassesFKIndex1 FOREIGN KEY (grade_id)
REFERENCES Grades (grade_id),
CONSTRAINT Classes_have_gradesFKIndex2 FOREIGN KEY (class_id, teacher_id)
REFERENCES Classes (class_id, teacher_id)
)
Query Analyzer spits out: Quote: Originally Posted by Query Analyzer There are no primary or candidate keys in the referenced table 'Classes' that match the referencing column list in the foreign key 'Classes_have_gradesFKIndex2'. Now, I know in SQL Server 2000 you can only have one primary key. Does that mean I can have a multi-columned Primary key (which is in fact what I would like) or does that mean that just one field can be a primary key and that a table can have only the one primary key?
In addition, what is a "candidate" key? Will making the other fields "Candidate" keys solve my problem?
Thank you for your assistance.
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Jul 20, 2005
Does anyone know a select statement that would return the column namesand keys and indexes of a table?Thanks,TGru*** Sent via Developersdex http://www.developersdex.com ***Don't just participate in USENET...get rewarded for it!
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Mar 1, 2015
I am designing a package to export staging tables into a flat file.The names of the tables will be: TableAStaging_YYYYMM and TableBStaging_YYYYMM. As you can see the names of the tables will be changing each month.
The flat files will have similar naming: C:MyPathFlatFileTableAStaging__YYYYMM and C:MyPathFlatFileTableAStaging__YYYYMM.I want to run the package as an sql job in two steps, one for each table.I need to dynamically pass the table names and file names (together with the path) to the IS package.
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Jan 22, 2004
Hi
I was wondering if anyone has an idea of how we could find the table names and column names of the tables in our Sql server database at runtime/dynamically given our connection string? Please let me know.
Thanks.
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Jan 21, 2004
I'm trying to do an update query that looks like this:
UPDATE
PAEMPLOYEE
SET PAEMPLOYEE.LOCAT_CODE = EMPLOYEE.PROCESS_LEVEL
FROM
PAEMPLOYEE A
JOIN EMPLOYEE B ON A.EMPLOYEE = B.EMPLOYEE
It's erroring out on the Employee prefix B.EMPLOYEE saying:
..."does not match with a table name or alias name used in the query"
Is it wrong or will it cause problems to have a field name the same as the table name?
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Jul 16, 2014
what the best practice is for creating indexes on columns that are foreign keys to the primary keys of other tables. For example:
[Schools] [Students]
---------------- -----------------
| SchoolId PK|<-. | StudentId PK|
| SchoolName | '--| SchoolId |
---------------- | StudentName |
-----------------
The foreign key above is as:
ALTER TABLE [Students] WITH CHECK ADD CONSTRAINT [FK_Students_Schools]
FOREIGN KEY([SchoolId]) REFERENCES [Schools] ([SchoolId])
What kind of index would ensure best performance for INSERTs/UPDATEs, so that SQL Server can most efficiently check the FK constraints? Would it be simply:
CREATE INDEX IX_Students_SchlId ON Students (SchoolId)
Or
CREATE INDEX IX_Students_SchlId ON Students (SchoolId, StudentId)
In other words, what's best practice for adding an index which best supports a Foreign Key constraint?
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Aug 31, 2007
Hello,
Maybe anyone have done that before?
I have table where i store SOURCE_TABLE_NAME and DESTINATION_TABLE_NAME, there is about 120+ tables.
i need make SSIS package which selects SOURCE_TABLE_NAME from source ole db, and loads it to DESTINATION_TABLE_NAME in destination ole db.
I made such SSIS package. set ole db source data access mode to table or view name variable.
set ole db destination data access mode to table or view name variable. set to variables defoult values (names of existing tables)
but when i loop table names is changed, it reports error, that can map columns, becouse in new tables is different columns.
how to solve that problem?
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Apr 10, 2008
How do I use table names stored in variables in stored procedures?
Code Snippetif (select count(*) from @tablename) = 0 or (select count(*) from @tablename) = 1000000
I receive the error 'must declare table variable '@tablename''
I've looked into table variables and they are not what I would require to accomplish what is needed.
After browsing through the forums I believe I need to use dynamic sql particuarly involving sp_executesql. However, I am pretty new at sql and do not really understand how to use this and receive an output parameter from it(msdn kind of confuses me too). I am tryin got receive an integer count of the records from a certain table which can change to anything depending on what the user requires.
Code Snippet
if exists(Select * from sysobjects where name = @temptablename)
drop table @temptablename
It does not like the 'drop table @temptablename' part here. This probably wouldn't be an issue if I could get temporary tables to work, however when I use temporary tables i get invalid object '#temptable'.
Heres what the stored procedure does.
I duplicate a table that is going to be modified by using 'select into temptable'
I add the records required using 'Insert into temptable(Columns) Select(Columns)f rom TableA'
then I truncate the original table that is being modified and insert the temporary table into the original.
Heres the actual SQL query that produces the temporary table error.
Code Snippet
Select * into #temptableabcd from TableA
Insert into #temptableabcd(ColumnA, ColumnB,Field_01, Field_02)
SELECT ColumnA, ColumnB, Sum(ABC_01) as 'Field_01', Sum(ABC_02) as 'Field_02',
FROM TableB
where ColumnB = 003860
Group By ColumnA, ColumnB
TRUNCATE TABLE TableA
Insert into TableA(ColumnA, ColumnB,Field_01, Field_02)
Select ColumnA, ColumnB, Sum(Field_01) as 'Field_01', Sum('Field_02) as 'Field_02',
From #temptableabcd
Group by ColumnA, ColumnB
The above coding produces
Msg 208, Level 16, State 0, Line 1
Invalid object name '#temptableabcd'.
Why does this seem to work when I use an actual table? With an actual table the SQL runs smoothly, however that creates the table names as a variable problem from above. Is there certain limitation with temporary tables in stored procedures? How would I get the temporary table to work in this case if possible?
Thanks for the help.
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Sep 14, 2015
I have a function that returns a table from a comma-delimited string.
I want to take this a step further and create a function that will return a set of tablenames in a table based on a 'group' parameter which is a simple integer...1->9, etc.Obviously, what I am doing is not working out.
CREATE FUNCTION dbo.fnReturnTablesForGroup
(
@whichgroup int
)
RETURNS @RETTAB TABLE (
TABLENAME VARCHAR(50)
[code]....
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May 16, 2008
Pls let me know How I generate script for All primary keys and foreign keys in a table. Thereafter that can be used to add primary keys and foreign keys in another databse with same structure.
Also how I script default and other constraints of a table?
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Jun 13, 2006
There is itemlookup table, which stores item number and itemdescription. Also there is a child table, pricehistory, of theitemlookup table, which stores different prices and different dateranges. So it is one-to-many relationship. (Price can be stored morethan one with a different date range)And there is another table RequestItem that stores the foreign key ofthe itemlookup table to show the information of the itemlookup table.Then how do I know later which date range of the price was stored inthe RequestItem table? Since I only keep the foreign key of theitemlookup table, it will be impossible to keep track of the row of thepricehistory table if there are more than one data existed in thepricehistory table.Will it be a valid table structure to create a column for the foreignkey of the pricehistory in RequestItem table or any other ways tohandle this issue?
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Dec 12, 2007
hi
I could not build a query using the system tables; where I can know how many foreing keys does a specific table has? I´m lost.
can somebody help me... thanks
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May 25, 2008
Hello,
It is possible to write stored procedures which take table names as parameters; is it also possible to do this with table valued functions?
For example, a simple stored procedure is this:
CREATE PROCEDURE SelectTop(@tableName sysname)
AS
BEGIN
Execute('Select top 10 * from ' + @tableName + ';')
END
I want to be able to do the analogous thing with a table valued function (so that I can query the result set, without having to create a temp table). How should I do this (i.e., pass a tablename as an argument to a table valued function)?
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Dec 13, 2007
I'm using SqlDatasource when the update process is on a primary key, how do you cascade the changes to other tables?
Also when deleting does the cascade deletes the row from another table or only sets the primary key to NULL?
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Aug 16, 2004
I have two tables as below. I want to update a quote and change the item for which it is for. So I want to do an update statement to change the cat_ref that the quote is for. However, when I do this I get a foreign key conflict with cat_ref in the item table. How do I get around this? Thanks
Code:
CREATE TABLE Item (
cat_ref VARCHAR(5)PRIMARY KEY,
descrip VARCHAR(50),
date_added SMALLDATETIME,
cat_type VARCHAR(20))
CREATE TABLE has_quote (
quote_id INT IDENTITY (1,1) PRIMARY KEY,
date_last_pricecheck SMALLDATETIME,
cat_ref VARCHAR(5)FOREIGN KEY
REFERENCES Item(cat_ref)
ON DELETE CASCADE,
first_name VARCHAR(10),
surname VARCHAR(10),
FOREIGN KEY (first_name, surname)
REFERENCES Customer(first_name, surname)
ON DELETE CASCADE
ON UPDATE CASCADE)
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May 30, 2007
How do I create a table with a foreign key
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Jul 15, 2012
I have a table fields Register_date, Std_ID, course, version, CourseLearningDays, Batch_Time and Trainer_IDHOw to make Register_date and Batch_Time as primary key in the table.. What are the necessary datatype for these two fields.And one more do we have datatype called date and time in MS SQL Server...
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Apr 17, 2014
I have two tables:
tbl_Vehicles (primary table)
tbl_DealerFeed_temp (temporary table)
I load values from a TXT file into the temporary table. From there, I figure out which records are new and need to be added to the primary table, and which records are duplicates, and need to a) update the primary table and b) be deleted from the temporary table.Basically, I need to write a SQL statement to grab the records that exist in BOTH tables based upon two primary criteria:
d_id in temporary table = d_id in primary table
df_t_v_stock_number in temporary table = v_stock_number in primary table
There are several fields that must be updated if the d_id and v_stock_number match:
v_price
v_internet_price
v_other_price
v_mileage
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Feb 5, 2008
Hello,
I have a very elementary question on table design. This screenshot (which is part of a larger diagram) sets the context of the question.
There are two distinct groups of products with different attributes, hence two separate tables: Products_A and Products_B.
There's a third table that keeps track of daily production (DailyProduction), which must accept items from either product table. Now, my question is: How do I relate these two tables to "DailyProduction" ? If I place a double-constraint with two foreign keys, then I get an error whenever I attempt to insert a record in DailyProduction. For example, if the new item is of "Products_A" type, then the error message from SSMS is:
No row was updated.
The data in row 1 was not committed.
Error Source: .Net SqlClient Data Provider.
Error Message: The INSERT statement conflicted with the FOREIGN KEY constraint "FK_DailyProduction_Products_B". The conflict occurred in database "MyDatabase", table "dbo.Products_B", column 'ProductB_ID'.
The statement has been terminated.
Correct the errors and retry or press ESC to cancel the change(s).
It's clear that the error message makes sense as SQL is trying to apply BOTH constraints. It's one AND the other, not one OR the other. Now, how do I remedy this ? What would be the most appropriate way to relate the three tables ?
Thanks.
Fernando
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Jul 15, 2002
Can somebody explain to me how to best do inserts where you have primary keys and foreign keys.l'm battling.
Is there an article on primary keys/Pk ?
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Nov 22, 2007
Hello!I have a table A with fields id,startdate and other fields. id and startdateare in the primary key.In the table B I want to introduce a Foreign key to field id of table A.Is this possible? If yes, which kind of key I have to build in table A?Thx in advance,Fritz
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May 21, 2008
i'm using sql express, management studio express and a visual web developer starter kit.
i have 4 tables: items; categories; categorization; old_items
the old_items table has both the item id and category fields in it, the new db has them separated: items.id; categories.id; categorization.itemId, categorizaton.parentCategoryId, both of which are foreign keys.
i need to get the old_item.id and old_item.category values into the new categorization table but it keeps choking on the foreign keys and i can't get past it. as far as i've been able to figure out so far, i need to turn off the foreign keys to do the insert but i'm not sure and i haven't been able to find any sql query examples that demonstrate it or explain it well enough for my n00b self.
i've read http://msdn.microsoft.com/en-us/library/10cetyt6.aspx, "How to: Disable Foreign Key Constraints with INSERT and UPDATE Statements" but i don't get how that affects it, it seems like one of the other options would actually disable them.
can anyone help? i've been trying all the permutations of queries i can think of and not getting it.
thanks.
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Jun 6, 2004
We have a SQL Server 6.5 table, with composite Primary Key, having the Duplicate Entry for the Key. I wonder how it got entered there? Now when we are trying to import this table to SQL2K, it's failing with Duplicate row error. Any Help?
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Jan 2, 2008
I have a problem with multiple databases on a server. I originally read another post that went into detail on this same error. After reading the post I decided to re-index the table to see if that would fix my issue. I started on Saturday by re-indexing a table on database 'a' - the process completed after that; I received another error on database 'b' on Monday i subsequently re-indexed all indexes on this database; today I have received the same message on database 'c' and 'd'. All post that I have read seem to point to an issue with only one database and not multiple databases. I have approximately 100 databases on this cluster - SQL 2000. The physical server logs only error shown is '000009ac.00001744::2007/12/29-15:12:58.848 ERR [CP] CppReadCheckpoint unable to copy file U:Disk12Partition1d61e68e-a60f-4ca6-b9ae-df3b893e4bb2 0000001.CPT to C:DOCUME~1mscsLOCALS~1TempCLS302F.tmp, error 3
000009ac.00001744::2007/12/29-15:12:58.848 ERR [CP] CppReadCheckpoint - Was that due to quorum resource not being up ???
' before corruption of database 'a'.
Here is the entire error if you think it will help. The error has been the same on all databases: 12/28/2007 6:23 AM A possible database consistency problem has been detected on database ‘ substituted_name'. DBCC CHECKDB and DBCC CHECKCATALOG should be run on database 'substituted_name'..
When I run the DBCC CHECKDB command I got these errors on Substite name database:
DBCC results for 'FVD_A'.
Msg 2511, Level 16, State 1, Line 1
Table error: Object ID 165575628, Index ID 2. Keys out of order on page (1:12743984), slots 97 and 98.
There are 72920059 rows in 2281375 pages for object 'FVD_A'.
CHECKDB found 0 allocation errors and 1 consistency errors in table 'FVD_A' (object ID 165575628).
DBCC results for 'FVD_CVS322'.
Msg 2511, Level 16, State 1, Line 1
Table error: Object ID 181575685, Index ID 2. Keys out of order on page (1:7250519), slots 30 and 31.
I am at a loss. I believe we may have a bigger issue, but the SAN Administrator and Server Admin are saying there is nothing they can do. Do I have a true SQL Server issue or something else.
HELP!
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Jul 23, 2005
Hey,I am having some confusion about how to formulate this particularquery.I have 2 tables. Table A has 4 columns say a1,a2,a3,a4 with thecolumns a1,a2,a4 forming the primary key. Table B again has 3 columnswith b1,b2,b3,b4 and like before, b1,b2 and b4 form the primary key.All columns are of the same datatype in both tables. Now I want to getrows from table A which are not present in table B. Whats the best wayof doing this?Thanks--Posted using the http://www.dbforumz.com interface, at author's requestArticles individually checked for conformance to usenet standardsTopic URL: http://www.dbforumz.com/General-Dis...pict235166.htmlVisit Topic URL to contact author (reg. req'd). Report abuse: http://www.dbforumz.com/eform.php?p=815725
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Apr 18, 2007
Kinda new to SQL, using SQL Server 2005.I have some foreign keys in a couple of tables. I need to drop thesetables, but can't since I'll get the error:Msg 3726,Level 16, State 1, Line 1Could not drop object 'Client' because it is referenced by a FOREIGNKEY constraint.I'm not sure how to disable or get rid of these foreign keys so that Ican drop my tables. I tried:ALTER TABLE Client NOCHECK CONSTRAINT ALLAlter Table Client Drop Column Foreign Key Boss_ID;I went into the Object Explorer and deleted the FK lines from eachtable, but still the same error.What am I doing wrong?Thanks for your help.
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Apr 18, 2006
Table partitioning with multiple key coulmns
Hi champs!
I have one table with around 600 million records.
I want to partition this table on 5 different coulumns.
year, month. coulumn3, coulumn4 and coulumn5.
How do I do this best?
What is the best way of doing this; is there any best practice on ths?
The obvious thing is to make a partition funktion based on the year and month coulmns, but I also want to partition on coulumn3, coulumn4 and coulumn5.
Many thanks
Kurlan
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Nov 5, 2004
Hi there. I haven't been able to figure out how to join a table on column on multiple table names. Here's the situation:
I have a table "tblJob" with a key of jobID. Now for every jobID, the program creates a new table that keeps track of the stock before the jobId was processed and after it was processed to give accurate stock levels and show the difference in stock levels. So, a jobID of 355 would be related to the table: "tblPreStock_335" and "tblPostStock_335". These 2 tables have all the materials in stock and the quantity. Therefore they show how much material was used. I need to figure out the difference in the material in the stock before and after the processing.
That means that I have to get a stockID, get the associated pre and post tables, and then display the difference of ALL the materials in the pre and post tables.
Could someone help me get started on the right path? Even a link to similiar problem that I haven't found would be nice.
Thx
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Mar 27, 2006
What is the best way to detect that a sqlserver table row has foreign keys and cannot be deleted?Thanks,Keith
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Feb 1, 2007
Hi,
I am trying to execute following sql script in sql-server 2000 query analyzer
CREATE TABLE user_courses (user_id varchar(30) NOT NULL PRIMARY KEY,
course_id varchar(10) NOT NULL PRIMARY KEY)
Its give's me following error :-
Cannot specify multiple primary key constraint
Hence I am not able to ceate table with multiple primary keys. So can any one tell me how to get this done?.
Secondly, Primary key must be unique i.e duplicate values are not allowed in P.K field. But in this case since I am declaring two fileds as primary keys.
Will it allow me to have following records in the user_courses table?
user_id(P.K) course_id(P.K)
bob CRS235
alice CRS235
Tim CRS235
tom CRS635
So, if we consider both the fields as primary keys together than I am not voilating Uniqueness constraint. But, if I look at course_id alone then I am voilating uniqeness property?
Thanks,
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Dec 15, 2014
I'm trying to create a table in Microsoft Server Management Studio 2012. The table has two fields which are both foreign keys.
I created the following:
create table tblRoomEquipment(
RoomID nvarchar(8),
EquipmentType nvarchar(1),
foreign key (RoomID) references tblRoom(ID),
foreign key (EquipmentType) references tblEquipment(Type)
)
Both tblRoom and tblEquipment have the red line error which when I highlight say the they both reference an invalid table!
Both tables are there and have primary keys defined as ID & Type. I have searched around and all I could find was that there maybe a permission problem.
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Jul 29, 2015
We had a server give out on us completely. All that is left is a back up of the SSRS database. We have been able to get a new SSRS environment working but the symmetric key doesn't seem to work. Reports will run if we delete all sensitive data through the Config manager and reenter the connection strings into the datasource but if we can get the symmetric key saved in the ReportingServices database to work correctly it will save us a ton of effort. Can we make use of the symmetric key saved in the ReportServer.dbo.Keys table?
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