unique index oracle
CREATE [UNIQUE | BITMAP] INDEX [schema.]index_name. ON [schema.]table_name(column [,column...]); UNIQUE : 建立唯一索引,唯一索引所參考到的欄位不能 ... ,Oracle Database enforces a UNIQUE key or PRIMARY KEY integrity constraint on a table by creating a unique index on the unique key or primary key.
| 相關軟體 MySQL 資訊 | |
|---|---|
 unique index oracle 相關參考資料
CREATE INDEX
Restrictions on Unique Indexes Unique indexes are subject to the following ... Oracle does not index table rows in which all key columns are null except in the ... https://docs.oracle.com CREATE INDEX介紹 - Oracle SQL學習筆記本
CREATE [UNIQUE | BITMAP] INDEX [schema.]index_name. ON [schema.]table_name(column [,column...]); UNIQUE : 建立唯一索引,唯一索引所參考到的欄位不能 ... http://mylinoraclesql.blogspot Creating Indexes
Oracle Database enforces a UNIQUE key or PRIMARY KEY integrity constraint on a table by creating a unique index on the unique key or primary key. https://docs.oracle.com How can I create a unique index in Oracle but ignore nulls ...
2018年11月2日 — We can do this with a function-based index. The following makes use of NVL2() which, as you know, returns one value if the expression is not ... https://stackoverflow.com How to Create and Use Indexes in Oracle Database | Oracle ...
https://blogs.oracle.com Oracle PLSQL: Indexes - TechOnTheNet
Syntax. The syntax for creating an index in Oracle/PLSQL is: CREATE [UNIQUE] INDEX index_name ON table_name (column1, column2, ... column_n) [ ... https://www.techonthenet.com Oracle Database 的Primary Key 與Unique Index 差異 - 昭佑.天翔
2010年3月24日 — 對於Oracle Database 的Primary Key 與Unique Index, 兩者所對應的欄位, 都必須是唯一值, 而這兩者之間的差異, 目前已知有二點: 差異項目. 1) https://tomkuo139.blogspot.com Oracle DB 的Index 相關指令(create 與alter) - 昭佑.天翔
2010年3月31日 — 在Oracle Database 中, 常會利用Index 提供查詢速度, 而對於Index 的建立與重建, 參考如下: 建立Index 語法. create [unique] index <index_name> https://tomkuo139.blogspot.com Oracle UNIQUE Index - Oracle Tutorial
Introduction to Oracle UNIQUE index. An index can be unique or non-unique. A unique index ensures that no two rows of a table have duplicate values in the ... https://www.oracletutorial.com unique index - Ask TOM - Oracle
When you specify a unique constraint on one or more columns, Oracle implicitly creates an index on the unique key. If you are defining uniqueness for purposes of ... https://asktom.oracle.com |