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I have a table with sets of settings for users, it has the following columns:
UserID INT Set VARCHAR(50) Key VARCHAR(50) Value NVARCHAR(MAX) TimeStamp DATETIME
UserID together with Set and Key are unique. So a specific user cannot have two of the same...
Started by Gidon on
, 10 posts
by 10 people.
Answer Snippets (Read the full thread at stackoverflow):
Creating a UNIQUE INDEX along ....
Using surrogate primary key will result in an extra column which is not used for other purposes.
Should I create a primary key on all three columns (userid, set, and key)
Make this one.
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I have a table which needs 2 fields. One will be a foreign key, the other is not necessarily unique. There really isn't a reason that I can find to have a primary key other than having read that "every single tabel ever needs needs needs a primary key...
Started by Chris Sobolewski on
, 9 posts
by 9 people.
Answer Snippets (Read the full thread at stackoverflow):
But then again i dont know please have a primary key in every table :)
It also helps forward compaitability in case identifier I would say that it'....
A composite primary key , which is based on the FK and the other field ..
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So I've seen several mentions of a surrogate key lately, and I'm not really sure what it is and how it differs from a primary key.
I always assumed that ID was my primary key in a table like this:
Users ID, Guid FirstName, Text LastName, Text SSN, Int...
Started by Nate Bross on
, 7 posts
by 7 people.
Answer Snippets (Read the full thread at stackoverflow):
The primary key is used a "glossary" of all the various keys and what they mean - you'll find natural, surrogate, primary key have....
An artificial key), and it should be your primary key, too.
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I have a table with 16 columns. It will be most frequently used table in web aplication and it will contain about few hundred tousand rows. Database is created on sql server 2008.
My question is choice for primary key. What is quicker? I can use complex...
Started by Siblja on
, 9 posts
by 9 people.
Answer Snippets (Read the full thread at stackoverflow):
I ....
);
A primary key which to change.
CREATE TABLE Records ( recordId INT NOT NULL PRIMARY KEY, ...
Why not just a single INT auto-generated primary key? INT is 32-bit, so it can handle over 4 billion records.
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Hello. I'm creating a VIEW out of 3 TABLES. Each TABLE has it's primary key. However, in the VIEW in order to have a primary key, I'll have to use a composite primary key (combination of primary keys of 3 TABLES).
I would however like to add a column ...
Started by Kabeer on
, 4 posts
by 4 people.
Answer Snippets (Read the full thread at stackoverflow):
I'm not sure how this translates to MySQL)
Views don't have... .
What exactly do you need a Primary Key)
(although, I'm talking SQL Server...
This is not a primary key, it is not consistant and will change when the data changes.
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Does Postgres automatically put indexes on Foreign Keys and Primary Keys? How can I tell? Is there a command that will return all indexes on a table?
Started by Grasper on
, 5 posts
by 5 people.
Answer Snippets (Read the full thread at stackoverflow):
Thus, it is not necessary to create an index explicitly for primary key_name>
in "psql" shows ....
Says: PostgreSQL automatically creates an index for each unique constraint and primary key constraint to enforce uniqueness.
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When creating a mysql dump containing the structure of my database, one of the tables shows the following:
CREATE TABLE `completedTransactions` ( `paymentId` int(10) unsigned NOT NULL, `timestamp` int(15) unsigned NOT NULL, `actionTaken` varchar(25) NOT...
Answer Snippets (Read the full thread at stackoverflow):
Yes, the KEY keyword is just an alias for ....
The key attribute PRIMARY KEY can also be specified as just KEY when given is not unique, PRIMARY KEY and UNIQUE KEY are uniques.
A synonym for INDEX.
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I have two already-existing tables which look (in part) roughly like this:
CREATE TABLE parent ( old_pk CHAR(8) NOT NULL PRIMARY KEY ) ENGINE=InnoDB; CREATE TABLE child ( parent_key CHAR(8), FOREIGN KEY (parent_key) REFERENCES parent(old_pk) ON UPDATE...
Started by wisnij on
, 3 posts
by 3 people.
Answer Snippets (Read the full thread at stackoverflow):
Dropping the primary key:
mysql> CREATE TABLE parent ( -> old_pk CHAR(8) NOT NULL PRIMARY KEY TABLE parent DROP PRIMARY KEY; Query OK, 1 row affected (0.01 sec) Records: 1 Duplicates: 0 Warnings: 1 Warnings....
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Say I have a table with a primary key a_id and foreign key b_id .
It is important that a_id and b_id never intersect, i.e. it should never be the case that there exists an a_id = b_id .
What would be the best way to implement this? Could I somehow do ...
Started by es11 on
, 6 posts
by 6 people.
Answer Snippets (Read the full thread at stackoverflow):
Upon insertion of a record, it would insert into that "key table would be two key inserts....
I'm not 100% sure about MySQL, but with Oracle you can that has the auto-increment field .
For adding a 3rd table with yet another unique key.
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I have a primary key name idnumber. how can I remove its primary key in mysql
Answer Snippets (Read the full thread at stackoverflow):
This should work for you, but are you sure you want to drop the primary key?
ALTER TABLE tablename DROP PRIMARY KEY;
Help on alter table syntax here
Why would you want to drop the the primary key? If you created....
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