Exploring the Implementation of Multiple Primary Keys in Oracle Database.（oracle两个主键）

Nowadays, databases are becoming increasingly complex, with new applications and emerging trends requiring more sophisticated approaches to access and retrieve data. Among the techniques employed for data access, multiple primary keys have become increasingly popular due to their ability to provide fast and accurate data retrieval. Oracle Database is a leading relational database system that supports the use of multiple primary keys. This tutorial will explore the implementation of multiple primary keys within an Oracle Database.

Multiple primary keys can be used for data partitioning and for more efficiently identifying rows in a table. In an Oracle Database, a Primary Key is a combination of one or more columns that uniquely identifies every row in a table. By implementing multiple primary keys, a data table can be further classified into smaller and more manageable categories. This is especially beneficial when dealing with tables that have a large volume of data.

To create multiple primary keys in an Oracle Database, a user must first create a table and identify which columns are desired primary keys. The user must then apply the primary key constraints to the columns by using the ‘ALTER TABLE’ command. The syntax for creating multiple primary keys is as follows:

ALTER TABLE table-name ADD CONSTRAINT constraint-name PRIMARY KEY (column1,column2,…);

Once the primary key constraints are applied, the user must then enable the keys by setting them to ‘enabled’ using the ‘ALTER TABLE’ command. This ensures that the primary keys will be enforced whenever data is inserted or updated into the table.

Finally, the user must create an index for the multiple primary keys. This is done by using the ‘CREATE INDEX’ command. The syntax for creating an index for multiple primary keys is as follows:

CREATE INDEX index-name ON table-name(column1,column2,…);

By following these steps, a user can easily implement multiple primary keys within an Oracle Database. This can result in improved query performance, enhanced data control, and easier maintenance when compared to single primary keys.

Overall, multiple primary keys are a great way to improve the efficacy and efficiency of an Oracle Database. By implementing multiple primary keys, users can partition their data into smaller and simpler segments, allowing for better and faster data retrieval. With these advantages in mind, any Oracle Database user should seriously consider incorporating multiple primary keys into their system.