We have a database where many tables have a field that has to be lengthened. In some cases this is a primary key or part of a primary key. The table in question is:-
/****** Object: Table [dbo].[DTb_HWSQueueMonthEnd] Script Date: 09/25/2014 14:05:09 ******/ SET ANSI_NULLS ON GO SET QUOTED_IDENTIFIER ON GO SET ANSI_PADDING ON GO CREATE TABLE [dbo].[DTb_HWSQueueMonthEnd](
[Code] ....
The script I am using is
DECLARE@Column varchar(100)--The name of the column to change DECLARE@size varchar(5)--The new size of the column DECLARE @TSQL varchar(255)--Contains the code to be executed DECLARE @Object varchar(50)--Holds the name of the table DECLARE @dropc varchar(255)-- Drop constraint script
[Code] ....
When I the the script I get the error message Could not create constraint. See previous errors.
Looking at the strings I build
ALTER TABLE [dbo].[DTb_HWSQueueMonthEnd] DROP CONSTRAINT PK_DTb_HWSQueueMonthEnd ALTER TABLE [dbo].[DTb_HWSQueueMonthEnd] Alter Column [Patient System Number] varchar(10) ALTER TABLE [dbo].[DTb_HWSQueueMonthEnd] ADD CONSTRAINT PK_DTb_HWSQueueMonthEnd PRIMARY KEY NONCLUSTERED ([Patient System Number] ASC,[Episode Number] ASC,[CensusDate] ASC) WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
They all seem fine except the last one which returns the error
Msg 8111, Level 16, State 1, Line 1 Cannot define PRIMARY KEY constraint on nullable column in table 'DTb_HWSQueueMonthEnd'. Msg 1750, Level 16, State 0, Line 1 Could not create constraint. See previous errors.
None of the fields I try to create the key on are nullable.
But the data type is not given to the script, so it is stuck.
I realize that syscolumns provides some relevant information, but it is not clear how to convert its information to a string like "decimal(12,4)". It seems, for example, that a decimal type has syscolumns.xtype = 106; however I can find no documentation on this, nor am I assured I can get all the right codes by trial and error. Does anyone know of a clear means of getting this information?
I have a producer table with a nullable column that stores SSN's. In some cases producers inherit SSN's from other producers. These records will have a null producer.ssn and a record stored in a child table to track the inheritance. Anyway, I've found two techniques to enforce uniqueness on a nullable column and wanted to get opinions as to which was better. First, write a trigger. Second, create a computed column that has a unique constraint on it. The computed column would use the SSN if not NULL Else use the PK identity value of the record. EXAMPLE DML:CREATE TABLE test ( ssn CHAR(9) NULL, testId INT identity(1,1) NOT NULL, ComputedConstraint AS CASE WHEN ssn IS NULL THEN CAST(testId AS CHAR(9)) ELSE ssn END, UNIQUE (ComputedConstraint)) Any comments would be greatly appreciated.
I am trying to recreate a primary key that I dropped in a table....
I'm using a statement like
ALTER TABLE temp WITH NOCHECK add CONSTRAINT PK__tempkey PRIMARY KEY CLUSTERED
(
num, store )
But apparently the "store" column was created without a "not null" and it let it create the PK during the table creation but now it won't let me add the PK with that nullable column..
Does anyone know how to get it to use that column to create a primary key after the initial table creation?
Here is the error i get
Cannot define PRIMARY KEY constraint on nullable column in table
Made 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?
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.
How do I improve a 3 column, composite clustered index on a large table when the developer insists there is no other way to achieve uniqueness? They say a uniqueindentifier column will not work.
Hi,I created a composite index (lastname, firstname). I know the followingqueries will use this index:WHERE lastname = ...WHERE lastname = ... AND firstname = ...Also this won't use the index:WHERE firstname = ...But how about: WHERE firstname = .. AND lastname = ...And why?Thanks a lot,Baihao--Posted via Mailgate.ORG Server - http://www.Mailgate.ORG
I have a table with a clustered composite index, consisting of 3 columns, which together form a unique key. For illustration, the columns are C1, C2 & C3.
Counts of distinct values for columns are C1 425, C2 300,000 & C3 4,000,000
C3 is effectively number of seconds since 01/01/1970.
The usage of the table is typically, insert a row, do something else, then update it.
Currently, the index columns are ordered C3,C1,C2. Fill factor of 90%.
My thinking is that this composite index is better ordered C1,C2,C3.
My reasoning is that having C3 as the leading column, biases all the inserts towards one side of the indexes underlying B-tree, causing page splits. Also, there'll be a bunch of "wasted" space across the tree, as the values going into C3 only ever get bigger (like an identity), so the space due to the fill factor in lower values never gets used.
I have just started on a project which will be based on an existing MS SQL Server database. It has many columns which can be, and sometimes are, null. My basic DataReader code throws an SqlNullValueException when I try to GetInt32 but not when I try GetString. Why the difference? Also, how do I model my class? Do I have to make all fields into nullable types? If I do that I notice a simple GridView will not show a column for that field! I am confused.
I am trying to add a DateTime? parameter to SqlCommand. It works when the variable has a value, but when its null, an exception gets thrown saying that parameter was not supplied.What is causing this error?
Hi all, I am using a SQL statement with a JOINs to display a summary list of Work Orders with some information from the related Purchase Order. I don't require that a Work Order be attached to a Purchase Order, so the JOIN field, POLineItemID, may not be present. My current problem is that my summary page does not show Work Orders that have a NULL value for POLineItemID -- ie, the JOINing field becomes required. How can I continue to use this JOIN structure but still return rows that don't have this JOIN field? Thanks in advance for your help. Here is my SQL statement for this... SELECT tblWorkOrder.WorkOrderNumber, tblWorkOrder.ActualCompletionDate, tblWorkOrder.EstimatedCompletionDate, tblWorkOrder.AssignedTo, tblWorkOrder.DelegatedTo, tblWorkOrder.Due, tblPurchaseOrders.PONumber, tblWorkOrder.POLineItemID, tblPOLineItems.POLineItemID AS Expr1, tblPOLineItems.PurchaseOrderID, tblPurchaseOrders.PurchaseOrderID AS Expr2, tblProducts.ProductID, tblProducts.ProductCategory, tblWorkOrder.ProductID AS Expr3, tblWorkOrder.WorkOrderStatusFROM (((tblWorkOrder INNER JOIN tblPOLineItems ON tblWorkOrder.POLineItemID = tblPOLineItems.POLineItemID) INNER JOIN tblPurchaseOrders ON tblPOLineItems.PurchaseOrderID = tblPurchaseOrders.PurchaseOrderID) INNER JOIN tblProducts ON tblWorkOrder.ProductID = tblProducts.ProductID)ORDER BY tblWorkOrder.Due
Is it bad design to allow nulls on a date field ? I can think of one case such as a sale of an item and populating a field for the date of purchase, only when the purchase took place (and null until then).
Hi All!General statement: FK should not be nullabe to avoid orphans in DB.Real life:Business rule says that not every record will have a parent. It isimplemented as a child record has FK that is null.It works, and it is simpler.The design that satisfy business rule and FK not null can beimplemented but it will be more complicated.Example: There are clients. A client might belong to only one group.Case A.Group(GroupID PK, Name,Code…)Client(ClientID PK, Name, GroupID FK NULL)Case B(more cleaner)Group(GroupID PK, Name, GroupCode…)Client (ClientID PK, Name, ….)Subtype:GroupedClient (PersonID PK/FK, GroupID FK NOT NULL)There is one more entity in Case B and it will require an additionaljoin in compare with caseAExample: Select all clients that belongs to any groupSummary Q: Is it worth to go with CaseB?Thank you in advance
Hi,I've enherited a big mess, a SQL Server 2000 database withapproximately 50 user tables and 65+ GB data, no explicitrelationships among entities (RI constraints whatsover), attempt tocreate an ERD would more than likely kill the relatively complexedapp, the owner would want to drop out of window, so,I don't intend to do that, you get the picture, sorry no DDLs thistime, and many tables have many nullable columns, joins slows down thesystem quite a bit, what's my best bet to improve its performance?change most of these nullable columns into non-nullable with defaultvalue of something like ' ', any thoughts along this line would beappreciated.
Could anyone tell me what governs whether a column is set as nullable or not nullable when creating a table using SELECT...INTO. It just seems to pick at random for me! I'm quite sure this is not the case. Is there a way to force a column to be non- nullable? I seem to be wasting a lot of time going through and altering the schema so I can use the columns in keys and indexes.
I have 4 particular columns (crt_dt,upd_dt,entity_active and user_idn) in many of the tables in my database. Now i have to find all the tables having four columns mentioned above and cases are
1) if the column is nullable., then it should result 'Y' 2) if the column is not nullable., then it should result 'N' 3)if column is not present., then it should display '-'
i am use this query to select the primary field colums in a table "select Column_Name as PrimaryKeycolumn from INFORMATION_SCHEMA.KEY_COLUMN_USAGE WHERE TABLE_NAME = 'tbl_Activity' and Constraint_Name like 'PK_%'"
but i want to select the fields which have a nullable=false for that i want know the information schema for null
Question.I have a new table that I am adding to a script that I wrote. Thistable has 3 fields, the first 2 fields are used in the on statement asbeing = other fields in the script.The first field always has data in it, but the 2nd field is sometimesnull.So my problem is if both fields have data in them and they both matchto the data in the fields that I am linking them to, then it returnsthe 3rd field without a problem. However if the 2nd field is null thenit is returning a null for the 3rd field. I have checked and the fieldthat I am linking to is null also.So if I haveselect t1.field1, t1.field2, t2.field1, t2.field2, t2.field3from table1 t1join table2 t2on t1.field1=t2.field1 and t1.field2=t2.field2with 2 records in each tabletable1: record1: data, datarecord2: data, nulltable2: record1: data,data,datarecord2: data,null,datawhat I get from the script isrecord1: data, data,data,data,datarecord2: data,null,data,null,nullI would expectrecord2: data,null,data,null,dataI hope this makes sense, I didn't want to post the entire actual scriptas it is about 150 lines long.Thanks in advance.
I would like to dynamically copy a table in Transact SQL, like this:
SELECT * into NEW_TABLE from MY_TABLE where 1 = 2
This creates an empty NEW_TABLE as desired. However, NEW_TABLE retains the column nullability of MY_TABLE; I would like NEW_TABLE to have all its columns nullable.
I tried to write Transact SQL logic to update the isnullable column in syscolumns for NEW_TABLE, but was told that the entire SQL Server would have to be reconfigured to allow this.
I have a dimension with a date field (int key value actually) that is generally null that I'm using to link to a time dimension. Everything works great when I set Null Processing to UnknownMember in the Measure Group Bindings, but if I try to set it to Preserve or anything else, I get processing errors because it can't match the null attribute key to the time dimension. I think I understand this, but I'm concerned that I'm not doing it the best way. Also, why does this page say "UnknownMember causes a data integrity error at processing time" when that's the only setting that does not give me errors?
I have a case where a table has two candidate primary keys,but either (but not both) may be NULL. I don't want to storea copy of the concatenated ISNULL'ed fields as an additionalcolumn, though that would work if necessary. Instead, I triedthe following (this is a related simplified example, not myreal one):CREATE FUNCTION ApplyActionPK(@IP int = NULL,@DNS varchar(64) = NULL)RETURNS varchar(74) -- NOT NULLASBEGINdeclare @val varchar(74)set @val = str(ISNULL(@IP, 0), 10)set @val = @val + ISNULL(@DNS, '')return @val-- Also tried "return str(ISNULL(@IP, 0), 10)+ISNULL(@DNS, '')"-- Also tried "return ISNULL(STR(@IP, 10), ISNULL(@DNS, ''))"-- ... and other things...ENDGOcreate table ApplyAction(-- An action applies to a computerAct varchar(16) NOT NULL,-- The action to applyIP int NULL,-- The computer IP address, orDNS varchar(64) NULL,-- The DNS name of the computerTarget as dbo.ApplyActionPK(ComputerID, DNS), -- PK value-- Also tried "Target as ISNULL(STR(@IP, 10), ISNULL(@DNS, ''))"CONSTRAINT PK_ApplyAction PRIMARY KEY(Act, Target))SQL Server always complains that the primary key constraint cannot becreated over a nullable field - even though in no case will the 'Target'field be NULL.Please don't explain that I should store an IP address as a string.Though that would suffice for this example, it doesn't solve myactual problem (where there are four nullable fields, two of whichare FKs into other tables).What's the reason for SQL Server deciding that the value is NULLable?What's the usual way of handling such alternate PKs?Clifford Heath.
I recently ran into an issue with an issue with a query against our Data Warehouse. When attempting to sum revenue from a table, and using a WHERE clause on a field that contains NULL values, the records with the NULL values are suppressed (in addition to whatever the WHERE clause specified). I believe this is because a NULL value is unknown so SQL doesn't know if it does or doesn't fit the criteria of there WHERE clause so it is suppressed.
That being said, is there a way to avoid this instead of having to add an ISNULL function in the WHERE clause which is going to kill performance?
Code: create table #nullTest ( name varchar(50) ,revenue int)
INSERT INTO #nullTest Values ('Tim',100) ,('Andrew', 50) ,(null, 200)
SELECT sum(revenue) as Revenue FROM #nulltest WHERE name <> 'tim'
Ideally, I would want the SELECT statement above to return 250, not 50. The only way I can think to accomplish this is with this query:
Code: SELECT sum(revenue) as Revenue FROM #nullTest WHERE isnull(name,'') <> 'tim'
I have a very large table that I need to partition. Ideally the table will write to three filegroups. I have defined the Partition function and scheme as follows.
CREATE PARTITION FUNCTION vm_Visits_PM(datetime) AS RANGE RIGHT FOR VALUES ('2012-07-01', '2013-06-01') CREATE PARTITION SCHEME vm_Visits_PS AS PARTITION vm_Visits_PM TO (vm_Visits_Data_Archive2, vm_Visits_Data_Archive, vm_Visits_Data)
This should create three partitions of the vm_Visits table. I am having a few issues, the first has to do with adding a new clustered index Primary Key to the existing table. The main issue here is that the closed column is nullable (It is a datetime by the way). So running the following makes SQL Server upset:
ALTER TABLE dbo.vm_Visits ADD CONSTRAINT [PK_vm_Visits] PRIMARY KEY CLUSTERED ( VisitID ASC, Closed ) ON [vm_Visits_PS](Closed)
I need to define a primary key on the VisitId column, but I need to include the Closed column in order to partition on it.how I would move data between partitions on a monthly basis. Would I simply update the Partition function, or have to to some sort of merge, split, or switch function?
I need to programatically create a mdb file which will contain nullable columns. I am using C++ with ADOX for the table creation and ADO to perform the table update.
Although ADOX seems to create the table ok, Table->Columns->Appends does not set the fields as adColNullable as expected.
When I insert data using ADO::Recordset->AddNew the following error occurs :- "The field 'MyTable.Column 2' cannot contain a Null value because the Required property for this field is set to True. Enter a value in this field."
Am I on the right tracks here or do I need to adopt a different approach?
