I have a deal table, each of these investments must be unique. I created a int pk : idDeal. Does that make sense or should i just use the deal colm being it has a unique constraint,
Reguarding indexes, should i make the auto # colm my pk and make that the clustered index? and put another index on the Deal Colmn? Any suggestions welcomed
Thank you
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.
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?
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?
View 1 Replies View RelatedAll of the 3 books I've read say it is not a good idea to create a clustered index on the primary key but it is created as the default. My question is has this changed in 2005? My understanding is to create the clustered index on columns used first in join clauses and then in where clauses, what is the answer?
View 14 Replies View RelatedI wanted to find all occurrences of ADRSCODE in a Database where ADRSCODE is in either an Index or a Primary Key.
I know how to get all of the occurences of ADRSCODE in a database and the table associated with it, I just want to tack on the Index and/or primary key.
SELECTOBJECT_NAME(object_id)FROMsys.columns
WHEREname
='foo'
How can I get the other bit of information ?
Hi everyone, I am trying to upgrade a 2000 DB to 2005 with SSIS Database Transfer.
I finally got it to work with an online transfer but the destination database has no primary keys, indexes or identity columns from the source DB.
What am I missing?
What other ways are there to upgrade a SS2000 DB to 2005?
Thank you.
Hi,
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.
Regards
Mike
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.
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?
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 ?
i have some confusions with keys and indexes.. plz let me know whether the following are correct..- Every Primary Key is a Clustered Index- A Primary Key cannot exist without a Clustered Index- Every Unique Key is a Non-Clustered Index - Non-Clustered Index is the DEFAULT Index- A table can have only 1 Primary key- A table can have only 1 Clustered Index- A table can have any number of Unique Keys- A table can have any number of Non-Clustered Indexes
Hello,
I am new in SQL Server, I have to deal with this big database with many tables, is there any way I can get a list of all primary keys , foreign keys and indexes and on all tables?
Thanks,
I'm trying to drop all indexes and primary keys so that i can rebuild them(from a script created from same database on another server).when i go to the 'generate sql scripts', it has the ability to drop orgenerate alltables. it also has the ability to generate all keys only. but i cant finda wayto drop all of these keys...any ideas?tiawoody rao
View 1 Replies View RelatedHello,I plan to create a table with 3 unique keys.Combination of three fields has to be unique for each row in a table thatare vendor ID (char 8), vendor name (char 40), and vendor office (5).Will it be okay to have a unique key which has a long character such asvendor name?How should I index those three fields? Those fields will be searched manytimes.RCW
View 2 Replies View Relatedis there a function that i can use in a store procedure that allow me to create an Indexes/Keys Property
thanx
Would anyone please instruct how to prevent the duplicate record bysetting the unique keys on the ms sql server? i've been checking theduplicate record as front-end and i found out if there is an internetdelay or some other reasons, it has a chance to store the duplicateddata into the database. so i realized it has to be done on the back-endside.for example, if i have three columns (office code, office id, officesection) as a unique key, how can i setup this? thanks in advance.
View 1 Replies View RelatedI have a primary key (column name is emp_id) in employee table. Also,I would like to make a combination of other two columns is unique.(combination of officecode field and claimno field must be unique).how can I implement this uniquess in ms sql 2000? thank you.
View 2 Replies View RelatedIf i create a simple table with a foreign key constraint, does itcreate an implicit index on that given ID? I've been told this isdone in some databases, but i need to know for sure if SQL Server doesit. Has anyone heard of this before, on any other databses perhaps?Heres an example of how the foreign key constraint is being added:ALTER TABLE [dbo].[administrators] WITH CHECK ADD CONSTRAINT[FPSLUFSUOXZGAJOJ] FOREIGN KEY([AdministratorRoleID])REFERENCES [dbo].[administratorroles] ([AdministratorRoleID])My initial testing seems to indicate adding an index on the foreignkey column helps, but i need to know for sure. Any insight would begreatly appreciated!Bob
View 6 Replies View RelatedI have a large table that consists of the columns zip, state, city, county. The primary
key "zip" has duplicates but the rows are unique.
How do I filter out only the duplicate zips. So in effect I only have one row per unique key.
Randy Garland
if you just want a list of all rows with duplicate zipcodes then ...
SELECT * FROM TableName WHERE zip IN ( SELECT zip FROM TableName
GROUP BY zip HAVING COUNT(*)>1 )
Duncan
Duncan, I tried this but it does not return one row per key.
Randy Garland
if i have a table which defines a rule as "combination of two fieldmust be unique", how can I write this in a constraint expressionsection?i started learning more about ms sql side to handle all the necessaryrules in back-end instead of front-end.also any good learning links, references, or book recommandations?thanks
View 5 Replies View RelatedIf you have a "Orders" table that is being sync'd to subscribers that are ocassionaly offline, and the subscribers add rows to their local Orders table. When they go online to sync with the published "Orders" table, how do you handle keeping the "OrderId" field unique?
Example:
Both salespeople sync the following data down:
OrderId Desc
1 Order 1
2 Test Order
Both salespeople go offline and add orders
Salesperson 1 adds:
OrderId Desc
3 Joes Order
Salesperson 2 adds:
OrderId Desc
3 Kathys Order
Now, when they go back online, they both will sync their orders up to the main database and they both have the OrderId of 3.
How do I go about protecting rows from deletion in this scenerio?
Rule 1 The Administrator Users Account may not be deleted
Rule 2 All Groups have Administrator as a member, and the Administrator cannot be removed.
Rule 3 All Groups have the Administrators Group as a member, and the Administrators Group cannot be removed.
Four tables:
Users Table (
UID bigint Identity seeded with 1234 Primary key
UserID varchar(30) NOT NULL UNIQUE
)
INSERT FIRST RECORD (this record needs to be protected from deletion)
UID = 1234
UserID='Admininstrator'
INSERT FIRST RECORD (this record and others can be deleted)
UID = 1235
UserID='Test User 1'
Groups Table (
GID bigint Identity seeded with 1234 Primary key
GroupName varchar(30) NOT NULL UNIQUE
)
INSERT FIRST RECORD (this record needs to be protected from deletion)
GID = 1234
UserID='Admininstrators'
INSERT SECOND RECORD (this record and others can be deleted)
GID = 1235
UserID='Test Group 1'
Group_Members Table (
GID bigint NOT NULL //points to the group's ID and can't be unique
UID bigint NOT NULL //points to the members UserID and can't be unique
)
INSERT FIRST RECORD (this record needs to be protected from deletion because UID points to the Administrator)
GID = 1234
UID = 1234
INSERT SECOND RECORD (this record and others can be deleted because UID does not point to the Administrator.)
GID = 1234
UID = 1235
Group_Group_Members Table (
GID bigint NOT NULL //points to the group's ID and can't be unique
GGID bigint NOT NULL //points to the group members GID and can't be unique
)
INSERT FIRST RECORD (this record needs to be protected from deletion because GGID points to the Administrators Group.)
GID = 1234
GGID = 1234
INSERT SECOND RECORD (this record and others can be deleted because GGID does not point to the Administrators Group.)
GID = 1234
GGID = 1235
I have tried using foriegn keys, constraints an every thing else, but I hit a brick wall because FK requires the ke to be primary (btw is UNIQUE).
Any help would be appreciated.
Why, in the process of creating a unique index, does SQL Server allowme to select the "Ignore duplicate keys" option? Wouldn't I justcreate a non-unique index if I wanted to ignore duplicate keys? Icame across this fact while preparing for the SQL Server design exam.
View 3 Replies View Related"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!
what do u think?
hmmm pls help!
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.
Thanks!
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.
Thanks
Hi everyone,
Does someone knows how can I drop a primary key (that I don't know the name) from a table in one sql statement.
Thanks,
Fady
HI ,
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:
Hi
How can 2 columns be clubbed together to form a primary key , i mean I have 2 columns job & Batch , need to club them together to form the primary key
How is it done I mean in the design , how to define that both the columns togethter form a primary key ,
Cause when I go to the table , it allows me to create a PK through the EM only for one column
Please help
Hi there,
is there any way I can use INSERT so if I try to copy duplicate primary key data, it automatically skips the task and moves on to the next data?