Creates an index on one or more computed or noncomputed columns in a table. Allows computed columns, like ordinary columns, to be index keys, and creates function-based indexes.A function-based index has one or more expressions as its index key.is an API for the Java programming language that defines how a client may access a database. The usage of a data source improves application's performance and scalability. It provides methods for querying and updating data in a database. From a technical point of view, the API is as a set of classes in the package. Using a datasource has several advantages over the package com.zetcode.datasourceex; import com.jdbc2.optional. To use JDBC with a particular database, we need a JDBC driver for that database. Mysql Connection Pool Data Source; import com.jdbc2.optional.
There's nothing inherently wrong with using auto-increment fields.The bigger problem is when people don't understand what they are doing with database access.It's like driving a car without really knowing the rules of the road.There's also nothing wrong with the main competetive idea, which is for the database to supply a primitive sequence of non-repeating identifiers, typically integers.This is rather like which side of the road you drive on. You might also want to check Java tutorial, Postgre SQL Java tutorial, Apache Derby tutorial, My SQL tutorial, or Spring Jdbc Template tutorial on Zet Code. In this example, we connect to the database using a data source.