Unique Key

Create Case-Insensitive Unique Index in Oracle

by Ed Chen
April 29, 2022May 27, 2023

Case Insensitive Index Using unique case-insensitive constraint in a column sometimes is reasonable in business logic to prevent duplicate items. Let's see a table that… Read More »

How to Resolve ORA-01502 Error Message

by Ed Chen
June 12, 2021February 6, 2023

ORA-01502: index or partition of such index is in unusable state ORA-01502 means that the index that the optimizer want to use is in UNUSABLE… Read More »

How to Resolve ORA-00001: unique constraint violated

by Ed Chen
May 2, 2020January 26, 2022
4 Comments

ORA-00001 There're only two types of DML statement, INSERT and UPDATE, may throw the error, ORA-00001: unique constraint violated. ORA-00001 means that there's a constraint… Read More »

How to Drop Primary Key in Oracle

by Ed Chen
April 22, 2020April 20, 2023

Drop Primary Key Primary key is sort of a constraint rather than an index, you should treat it as a constraint first so as to… Read More »

How to Add Primary Key in Oracle

by Ed Chen
April 22, 2020December 10, 2022

Add Primary Key There're 3 basic ways to create a primary key for a table. 1. System-Generated Name You don't have to provide a name… Read More »

How to Resolve ORA-01452: cannot CREATE UNIQUE INDEX; duplicate keys found

by Ed Chen
December 28, 2019December 10, 2022

ORA-01452 ORA-01452 means that the unique index that you want to impose on columns cannot be created because of duplicate keys have been found. In… Read More »

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