None of the fields that are part of the primary key can contain a null value but some of the fields that are part of the unique constraint can contain null values as long as the combination of values is unique. Moreover, Oracle does not permit you to create both a primary key and uni...
can anyone help me that how to drop unique constraint from an existing mysql table. And also how to find constraint name, active in which table, which field... etc. (in oracle which is in user_constraints table). I have tried alter table table_name drop constraint constraint_name. but ...
If there's an existingnot nullconstraint you want to remove, you can drop it online. To do this you need to find its name. Assuming – like most people – you defined the columnnot nullwithout a specific name, you'll have to look it up first. You can do this by checking the data...
unique, given_name varchar2(512) not null ); The table can only have one primary key. So at least one ofaccount_idandusernamemust be a unique constraint. But which should be theprimarykey? Theaccountstable is likely to have many child tables that refer to a particular row in it. Such...
query to find unique constraints on a table in oracle SQL> CREATE TABLE DEPT_MASTER ( dept_nr NUMBER UNIQUE, dept_name varchar2(100) NOT NULL, dept_status NUMBER(1,0) NOT NULL, created_at date ); Table created. SQL> select CONSTRAINT_NAME,INDEX_NAME,CONSTRAINT_TYPE from user_constraints...
RENAME TO Classmates; Output: Delete Table in Oracle We use the DELETE statement in the Oracle database to delete or remove records/records from a table. Syntax: DROP TABLE table_name; Parameters: table:The name of the table conditions:It refers to the conditions which must be met to get...
Add a Constraint to restrict a generic to numeric types Add a html content to word document in C# (row.Cells[1].Range.Text) Add a trailing back slash if one doesn't exist. Add a user to local admin group from c# Add and listen to event from static class add characters to String a...
MySQL error code 141 = Duplicate unique key or constraint on write or update MySQL error code 144 = Table is crashed and last repair failed MySQL error code 145 = Table was marked as crashed and should be repaired Note that error 135 (no more room in record file) and error 136 (no mo...
ALTER TABLE t1 ADD c2 int UNIQUE; As the output in Figure 5 indicates, the unique key gets added. Figure 5. Adding a new column as unique key Add a constraint to a column A constraint may be added with theALTER TABLE … ADD CONSTRAINTstatement. If the primary key was dropped earlier,...
Re: How to drop unique constraint 48151 Roland Bouman February 18, 2006 01:25PM Sorry, you can't reply to this topic. It has been closed. Content reproduced on this site is the property of the respective copyright holders. It is not reviewed in advance by Oracle and does not necessarily...