Oracle Alter Table Add Primary Key
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Listed below is an example of the SQL generated by the Oracle Alter Table Add Primary Key function: ALTER TABLE TESTUSER. As a result, no primary key column can be NULL. Also, you need to specify index name if there is more than one index fitting PK columns and you want a specific index to be used to enforce PK.
No, you do not need to precreate the index. Column c1 uses disk-based storage, since this is the default for the table determined by the table-level STORAGE DISK clause in the statement. NAME Age ------------- Peter 45 Bob 25 John 56 Peter 45 Some collegues suggest to add a PK with a sequences and triggers: This is nice, but my customers use a Database User with no rights to add sequences or triggers.
Oracle Alter Table Add Primary Key - For information about why this is sometimes useful, see Tuning Java DB. This is better for performance than running separate statements.
I have some columns with no primary key and want to add a primary key column. NAME Age ------------- Peter 45 Bob 25 John 56 Peter 45 Some collegues suggest to add a PK with a sequences and triggers: This is nice, but my customers use a Database User with no rights to add sequences or triggers. I want to prevent to contact dozens of DBA administrators to alter user rights or to run my scripts. This is my suggestion to add a PK with only an update statement: I need help in Step 2 Step 1: Create the ID column I have DB rights for this ALTER TABLE PERSON ADD ID NUMBER 10,0 ; Step 2: Question: Can I initialize the ID column with unique values based on the order of the rows or something else? This will be the result: ID PK NAME Age --------------------- 1 Peter 45 2 Bob 25 3 John 56 4 Peter 45 Thanks folks! THis idea is very childish, but should work fine if your table doesnot have large amount of rows. Even for a limited database with in my example 100 users, i could have 2 times: John - Age 56. The update above would then generate an identical primary key. But the solution above gives a different primary. Thanks for thinking together!
For information about why this is sometimes useful, see Tuning Java DB. ALTER TABLE ADD CONSTRAINT adds a table-level constraint to an existing table. A primary key can consist of one or more fields on a table. Derby also raises an error if you try to add a DEFAULT clause to a generated column. In the database world, the artificial keys are known as surrogate keys which are as opposed to natural primary keys. Anyone considering using the services of an Oracle support expert should independently investigate their credentials and experience, and not rely on advertisements and self-proclaimed expertise. Listed below is an example of the SQL generated by the Oracle Alter Table Add Primary Key function: ALTER TABLE TESTUSER. Then, you add the word DROP, and then the constraint type. This means we will be storing numbers in this column.
