How to map an enumeration type (Enum) in Java to a Column in database with Hibernate/JPA with two cases:
- The column stores string values
- The column stores number values
Last week I was working on the backend of a project(SEF AcadeMiX) which uses JPA and spring boot. There, I had to add translations of the data also into the database. (Actually, we had already created the relevant tables for that in the initial project) There was a separate table for languages and separate tables for translations. I’m sure this is not clear. So here’s a diagram.
Few days before we figured out something which we had missed that is we don’t need a separate table for languages because we hope to use only two languages. So we had a discussion and decided to use Enums for languages.
#hibernate #enum #enumeration #spring-boot #jpa
When generating a database using JPA, one of the most important things we have to do is mapping inheritances. In this post, you are going to learn some basic things that we have to know when mapping inheritance.
For the ScholarX project, I had to add JPA annotations to the spring-boot project in order to generate the MySQL database. The models had already been created for the entities. To initiate the task, I was given a class diagram. Otherwise, it might be so hard to find data types, relationships, etc. Click here if you wanna find out what a class diagram is.
Okay then… back to the topic. JPA has several inheritance strategies.
If you have checked our class diagram you may notice that we have a base modal called “BaseScholarxModel” for all entities. And there’s another parent called “EnrolledUser” extended by the base modal. We don’t need tables for these two models. Therefore I had to make use of those different strategies mentioned above.
A section of the class diagram
#programming #hibernate #spring #jpa #object-oriented
At the end of 2019, Python is one of the fastest-growing programming languages. More than 10% of developers have opted for Python development.
In the programming world, Data types play an important role. Each Variable is stored in different data types and responsible for various functions. Python had two different objects, and They are mutable and immutable objects.
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The Size and declared value and its sequence of the object can able to be modified called mutable objects.
Mutable Data Types are list, dict, set, byte array
The Size and declared value and its sequence of the object can able to be modified.
Immutable data types are int, float, complex, String, tuples, bytes, and frozen sets.
id() and type() is used to know the Identity and data type of the object
a**=str(“Hello python world”)****#str**
Numbers are stored in numeric Types. when a number is assigned to a variable, Python creates Number objects.
Python supports 3 types of numeric data.
int (signed integers like 20, 2, 225, etc.)
float (float is used to store floating-point numbers like 9.8, 3.1444, 89.52, etc.)
complex (complex numbers like 8.94j, 4.0 + 7.3j, etc.)
A complex number contains an ordered pair, i.e., a + ib where a and b denote the real and imaginary parts respectively).
The string can be represented as the sequence of characters in the quotation marks. In python, to define strings we can use single, double, or triple quotes.
# String Handling
#single (') Quoted String
# Double (") Quoted String
# triple (‘’') (“”") Quoted String
In python, string handling is a straightforward task, and python provides various built-in functions and operators for representing strings.
The operator “+” is used to concatenate strings and “*” is used to repeat the string.
'Output : Python python ’
#python web development #data types in python #list of all python data types #python data types #python datatypes #python types #python variable type
In this article, we’ll dive into Relationship Mapping with JPA and Hibernate in Java.
JPA is the persistence standard of the Java ecosystem. It allows us to map our domain model directly to the database structure and then gives us the flexibility of manipulating objects in our code - instead of messing with cumbersome JDBC components like Connection, ResultSet, etc.
#java #hibernate #database #jpa