As our DB has no primary keys or indexes ive taken a copy of all populated tables and tried to force primary keys within a new DB.
the problem is all off the tables have multiple datasets within them, a dataset for each year. This causes all instances of ID numbers to not be unique as they are replicated for every year they are active.
Its a school database so a student who has been here for 3 years will have 3 instances of his ID number, one for each years' data set.
So how do i force primary keys if there is no unique identifier? ive been highlighting both data set and ID columns and setting that combination as the primary key.
Essentially i need to analyse the relationships between the tabls in a diagram and also run some speed tests to see how fast the db works when it has indexes and primary keys.
the reason im writing is that ive done this on ten tables and with another 160 to do im just checking im doing the right thing?
I have recently been looking at a database and wondered if anyone can tell me what the advantages are supporting a unique collumn, which can essentially be seen as the primary key, with an identity seed integer primary key.
For example:
id [unique integer auto incremented primary key - not null], ClientCode [unique index varchar - not null], name [varchar null], surname [varchar null]
isn't it just better to use ClientCode as the primary key straight of because when one references the above table, it can be done easier with the ClientCode since you dont have to do a lookup on the ClientCode everytime.
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,
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,
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?
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?
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?
"Violation of PRIMARY KEY of restriction 'PK_Approve_Overtime'. The overlapping key cannot be inserted in object 'Dbo.Approve_Overtime'. The statement was ended." can soemone explain to me why i have this kind of error? i have this two tables. approve_overtime table has a primary key id_no and application_input table with a primary key of id_no! all the values from of application_input will be stored also in approve_overtime. sometimes the datas can be stored.sometimes it cannot and produces an error!
Using SQL Svr 7.0. It appears that primary keys are created as nonclustered unique indexes. Is there a configuration setting I can use to make them be created as clustered unique indexes?
If a table has a column defined as Int, Identity(1,1) which is to be used as the primary key, should that index be defined as clustered or non-clustered? In Enterprise manager when you create a PK on a table it defaults to being a clustered index. I am sure the answer depends on the other index requirements and columns in the table but I'd like to see what other ppl think about this.
I have read that SQL Server tables can't have more than one primary key. I know in Access two keys are allowed. Why can't there be two primary keys in a single table in SQL Server 7.
I accidently removed the primary keys from my table by mistake. Is there anyway ,That i can get the PK's back to what is used to be. Need Help pls...... When I try "resetting" the PK I kep getting this error:
'table_name' table - Unable to create index 'PK_tablename'. ODBC error: [Microsoft][ODBC SQL Server Driver][SQL Server]CREATE UNIQUE INDEX terminated because a duplicate key was found for index ID 1. Most significant primary key is '1'. [Microsoft][ODBC SQL Server Driver][SQL Server]Could not create constraint. See previous errors. [Microsoft][ODBC SQL Server Driver][SQL Server]Warning: The table 'tDetail' has been created but its maximum row size (12521) exceeds the maximum number of bytes per row (8060). INSERT or UPDATE of a row in this table will fail if the resulting row length exceeds 8060 bytes. [Microsoft][ODBC SQL Server Driver][SQL Server]The statement has been terminated.
In access you can have two fields that are primary keys with one or the other repeating as long as the combination is not repeated. i.e. key1 key2 200410 12345 200410 12346 200410 12588 etc for all 200410 there can not be a repeat of any value of key 2
is there a way to have this dual key in MSSQL :confused:
I have declared a table with a single column to be a Primary key. If I write 2 records, the first comprsing "A" and the second "a" then I get an exception about violating the uniqueness of the key. Is there a way that I can define the key to be case sensitive.
I have two tables with similar primary keys, table a and table b, and I want to find out all the key values that are disimilar between the tables. Can this be done with a select? if so what would it be.
I am not entirly sure what a forigen key is, is it a unique ID which is the same as the primary key? If adding a foreign key to a table that already has data, will it update each row with a unique ID or will it only create a unique ID on newly inserted records (for the foreign key)? If the foreign key is the same as the primary key then why do we need to even add a foreign key at all?For example a table like: Table Name : Customers--CustomerID uniqueidentity (primary Key)--FirstName nchar Table Name : Orders --OrderID int--CustomerID int Obviuously CustomerID are going to be the same in both tables, so why would you need to add a foreign key on 'CustomerID' to the 'Order' table, can't SQL match the customerID in each table any way? Cheers
HiI have a database and I been inserting some dummy data into it but now I want to upload it to my website but I want to delete all the dummy data and start the PK back at 1. I truancted all the data but it still keeps counting from the last one.So how do I reset it?
Hi, I have a question on pk? I have a db which has tables which do not have pk?I want to create Pk on each one of them - infact,I want to alter the table , add one more field and make it the pk . My question is - do I will have to go to each table,alter it and then create the pk on it or do someone have any script or better way to do it? Any help is appreciated.
Hi, Just a continuation to my earlier queries on replication. I have a db which I want to replicate - it do not have pk? I do not want to create pk on existing columns - so I thought of creating one more column in all the tables and make them pk . Any one has any idea if this will work fine or may give any problem which I should be prepare for. Any thought appreciated - pvd
I have a 3rd party app which had a primary key with about 5 fields. The last field of this was a trantype. This app had a posting process which uses this in it's sql. Ran rather slow. We added an individual index to this field and cut processing down 90%. It almost seemded like sl server was ignoring this index. Is this because it was the last field in the primary key index?
Hi All, I`m using BCP to import ASCII data text into a table that already has many records. BCP failed because of `Duplicate primary key`. Now, is there any way using BCP to know precisely which record whose primary key caused that `violation of inserting duplicate key`. I already used the option -O to output error to a `error.log`, but it doesn`t help much, because that error log contains the same error message mentioned above without telling me exactly which record so that I can pull that `duplicate record` out of my import data file. TIA and you have a great day. David Nguyen.
I have two tables (categories & listings) which create a many-to-many relationship.
I have created an interim table with the primary keys from each table as a composite primary key...(cat_id & list_id).
How does the interim table get populated with the id's?
When I do an insert statement to insert data into the categories table, the cat_id field is automatically generated...same with the listings table, but when (and how) does the primary key data get into the interim table.
I have a problem with the primary keys in my main Db , I want to setup replication and looks like someone tampered with my database by removing the primary keys.and in order to setup replication i need this table to have primary keys .THere are duplicates in that table but they are nessecary...and for this reason the primary keys do not want to "stick" when i try and specify them.Can anybody help
Can someone tell me what is the best way to check 2 tables lets say tb1 and tb2, to find those customers that are in tb1 but not in tb2 using four fields(cardno,spend,date,refno) as the primary key. Duplicates fields are in tb1
I'm working on a system that is very address-centric and detection ofduplicate addresses is very important. As a result we have brokenaddresses down into many parts (DDL below, but I've left out somereference tables for conciseness), these being state, locality, street,street number, and address. The breakdown is roughly consistent withAustralian addressing standards, we're working on finalising this.Because we carry the primary key down each of the levels, this hasresulted in our address table having a very wide primary key (around170 characters). We refer to addresses from a number of other tablesand although my instinct is to use this natural key in the other tablesI wonder if we should just put a unique index on the natural key,create a surrogate primary key and use it in the other table. Anythoughts?CREATE TABLE dbo.States (StateID varchar (3) NOT NULL ,StateName varchar (50) NOT NULL ,CONSTRAINT PK_AddressStates PRIMARY KEY NONCLUSTERED(StateID))CREATE TABLE dbo.Localities (Locality varchar (46) NOT NULL ,StateID varchar (3) NOT NULL ,Postcode char (4) NOT NULL ,CONSTRAINT PK_Localities PRIMARY KEY NONCLUSTERED(Locality,StateID,Postcode),CONSTRAINT FK_AddressLocalities_AddressStates FOREIGN KEY(StateID) REFERENCES dbo.States (StateID))CREATE TABLE dbo.Streets (StreetName varchar (35) NOT NULL ,StreetTypeID varchar (10) NOT NULL ,StreetDirectionID varchar (2) NOT NULL ,Locality varchar (46) NOT NULL ,StateID varchar (3) NOT NULL ,Postcode char (4) NOT NULL ,CONSTRAINT PK_Streets PRIMARY KEY CLUSTERED(StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode),CONSTRAINT FK_Streets_Localities FOREIGN KEY(Postcode,Locality,StateID) REFERENCES dbo.Localities (Postcode,Locality,StateID))CREATE TABLE dbo.StreetNumbers (StreetName varchar (35) NOT NULL ,StreetTypeID varchar (10) NOT NULL ,StreetDirectionID varchar (2) NOT NULL ,Locality varchar (46) NOT NULL ,StateID varchar (3) NOT NULL ,Postcode char (4) NOT NULL ,StreetNumber varchar (15) NOT NULL ,BuildingName varchar (100) NOT NULL ,CONSTRAINT PK_StreetNumbers PRIMARY KEY CLUSTERED(StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode,StreetNumber),CONSTRAINT FK_StreetNumbers_Streets FOREIGN KEY(StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode) REFERENCES dbo.Streets (StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode))CREATE TABLE dbo.Addresses (StreetName varchar (35) NOT NULL ,StreetTypeID varchar (10) NOT NULL ,StreetDirectionID varchar (2) NOT NULL ,Locality varchar (46) NOT NULL ,StateID varchar (3) NOT NULL ,Postcode char (4) NOT NULL ,StreetNumber varchar (15) NOT NULL ,AddressTypeID varchar (6) NOT NULL ,AddressName varchar (20) NOT NULL ,CONSTRAINT PK_StreetNumberPrefixes PRIMARY KEY CLUSTERED(StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode,StreetNumber,AddressTypeID,AddressName),CONSTRAINT FK_Addresses_StreetNumbers FOREIGN KEY(StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode,StreetNumber) REFERENCES dbo.StreetNumbers (StreetName,StreetTypeID,StreetDirectionID,Locality,StateID,Postcode,StreetNumber))
I have an application in which i need to get the foreign key fieldsfrom a table and then get all the foreign keys primary key field fromthe linking table. Could some one tell me how i do this usingINFORMATION_SCHEMA. I have tried and can get the foreign keys but notsure how to get the associated primary keys.
I have a question with regads to placement of data files/indexes onmultiple filegroups. Here is the current scenario:I have a database comprised of two filegroups - PRIMARY and INDEX. ThePRIMARY filegroup is comprised of two files, one residing on the Rdrive and another residing on the O drive. The INDEX filegroupconsists of a file on the S drive. The transaction logs reside on theT drive. The box itself has five individual drive slots, not RAID'edor mirrored. The tables are created in the PRIMARY filegroup, theindexes in the INDEX group.My question is this: is there any inherent benefit to create thePRIMARY KEYS in a different filegroup? Currently, they are beingcreated in the PRIMARY group along with the actual data tables.Thank you in adavance for any help.Anthony Robinson
What query do I use to list the primary key for each user table, i.e.TABLE | PRIMARY_KEY |Regards,Alan*** Sent via Developersdex http://www.developersdex.com ***Don't just participate in USENET...get rewarded for it!
I have the following issue - my database consists of tables with one ID field as primary key. for each INSERT the 'next' value from this ID field is extracted from a table called TableList. - this works perfectly fine, as long as I insert one record at a time: but now I would like to run a command such as INSERT INTO dest (name) SELECT name FROM src i.e. without being able to specify the ID value. Has anybody implemented this (i would prefer not to use identity columns or use cursors), possible with triggers?
In SQL Server 2000, I'm looking for input as to how to set up primary keys (PKs).
Is it safe to use the IDENTITY feature using AUTOINCREMENT as a setting for a PK, or is it best to generate my own and check for dups?
My concern is whether SQL Server at any point will taint the numbers used as the PK -- because as you know, these PKs are going to wind up linking into (relating into) other tables (e.g. client orders).
Certainly it's vital that the clientID not get lost/changed during any regular DB maintenance or use.
I upsized an Access database into MSDE to begin scalling it up to SQL Server.I have a curious problem: my queries don't return any results if the table has a Access primary key before they are upsized.I've deleted and re-created the database to check this, and if I use Access to remove the primary key before upsizing, the queries will return a result; if I re-instate the primary key and upsize again, the queries return nothing.(This is true regardless of using VS Net, Web Matrix, or by hand...)I'm a newbie with MSDE and with upsizing from Access. Is this expected -- or have I maybe done something wrong, again?- Tinker
