Common functions for oracle and mysql? - java

In below query I wanted to group by just on date not time that's why I used TO_DATE function
select TO_DATE(e.created_dt, 'dd-mm-yy'),sum(CURRENT_BAL) from sbill.act_resource_t e group by TO_DATE(e.created_dt, 'dd-mm-yy');
so as of now its working fine with oracle but as per our business requirements application should support both oracle and mysql without write two different queries;
so do we have any solution for that which should works with both oracle and mysql ?
Note :- I am using hql
Below code :
Query query1 = entityManager.createQuery("select TO_DATE(e.createdDt, 'dd-mm-yy'),sum(CURRENT_BAL) from ActT e group by TO_DATE(e.createdDt, 'dd-mm-yy')");
List<Object> result=query1.getResultList();

Since the functions differ between the databases, we need a dynamic query. But we can do it efficiently by creating a custom conversion method, which will select the right implementation based on the current database type. And the query itself will remain common (The solution uses FluentJPA library):
public static final FormatModel DD_MM_YY = Format.dateModel(Format.DD, Format.MM, Format.YY);
public static boolean isOracle() {
return false; //should return the actual value in runtime
}
#Local
// picks the right implementation
public static Function1<String, Date> AS_DATE() {
if (isOracle())
return s -> TO_DATE(s, DD_MM_YY); //oracle
return s -> STR_TO_DATE(s, "%d-%m-%y"); // mysql
}
Now we can write a generic implementation:
#Entity
#Table(name = "act_resource_t", schema = "sbill")
#Data
public static class ActResource {
#Id
private int id;
private int currentBAL;
private String createdDT;
}
// for the result
#Tuple
#Data
public static class BalanceByDate {
private Date date;
private int balance;
}
...
public BalanceByDate balanceByDate() {
FluentQuery query = FluentJPA.SQL((ActResource e) -> {
// with lambda we inject the right implementation
Date createdDate = alias(AS_DATE().apply(e.getCreatedDT()), BalanceByDate::getDate);
Integer balance = alias(SUM(e.getCurrentBAL()), BalanceByDate::getBalance);
SELECT(createdDate, balance);
FROM(e);
GROUP(BY(createdDate));
});
return query.createQuery(em, BalanceByDate.class).getSingleResult();
}
This is the resulting SQL for MySQL:
SELECT STR_TO_DATE(t0.created_dt, '%d-%m-%y') AS date, SUM(t0.current_bal) AS balance
FROM sbill.act_resource_t t0
GROUP BY STR_TO_DATE(t0.created_dt, '%d-%m-%y')

Related

Map Custom JdbcTemplate query result in an Object

I new in java and try to use spring framework. I have a question.
By example, I have table :
employee (id_employee, name)
employee_product (id_employee_product, id_employee, product_name)
if I select an employee data from my Employee table, I can map it in a POJO model User and define the tables structure in that model, like this:
public class Employee {
private final int id_employee;
private final String nama;
public Employee(int id_employee, String nama){
this.id_employee = id_employee;
this.nama = nama;
}
public int getId() {
return id_employee;
}
public String getNama() {
return nama;
}
}
And this is the map from jdbcTemplate:
final String sql = "SELECT id_employee, nama FROM employee";
return jdbcTemplate.query(sql, (resultSet, i) -> {
return new Employee(
resultSet.getInt("id_employee"),
resultSet.getString("nama")
);
});
That is clear example for select data from 1 table.
My question is, how to map data from query if my data is custom query? Such us using join and select custom field from that tables, Am I need to create POJO every query?
Sometimes I need to select only employee.id_employee, and employee.name field from my employee table.
And in another controller I need to select employee.id_employee from my employee table.
In another case, I need only select employee.name, and employee_product.product_name
Is there an alternative to map the data without creating POJO for every case?
Create a one POJO combining two tables like this
public class Employee {
private int id_employee;
private String name;
private int id_employee_product.
private String product_name
//getter and setters
//Don't create a constructor its Entiry
}
Now by using a BeanPropertyRowMapper Doc Link write your repository like
public List<Employee> fetchEmployeeProduct(){
JdbcTemplate jdbcTemplate = new JdbcTemplate("Your_DataSource");
StringBuilder query = new StringBuilder();
query.append("Your Query");
List<Employee> employeeProductList =
jdbcTemplate.query(query.toString(), new BeanPropertyRowMapper<Employee>(Employee.class));
}
Make sure SELECT clause in the query and Employee POJO's filed name is same.
Once if you execute your query it will automatically map to POJO. You no need to write a custom mapper BeanPropertyRowMapperwill take care of mapping.

ObjectBox: Get objects with specific relations

Expect the two entities Movie and Genre:
#Entity
public class Movie {
#Id
private long id;
private String name;
private ToMany<Genre> genres;
[...]
}
#Entity
public class Genre {
#Id
private long id;
private String name;
[...]
}
We all know how to create a relation and save it:
Movie movie = new Movie();
movie.setTitle("Star Wars");
movie.getGenres().add(new Genre("Sci-Fi");
box.put(movie);
but is there a possibility to query all Movie-objects with a specific Genre? Like
Box<Movie> box = boxStore.boxFor(Movie.class);
Query query = box.query()
.equal(Genre_.name, "Sci-Fi") // note that I want to query the Movie-Box with Genre-properties
.build();
List movies = query.find();
My goal is to find all movies with a specific genre in a simple way. Does anyone know how to do it or do I have to query all movies and filter the result on my own? Or do I have to adapt my entities in another way?
Update:
I prepared the correct marked answer below to a working example:
final Genre genreSciFi = genreBox.query().equal(Genre_.name, "Sci-Fi").build().findFirst();
List<Movie> filteredMovies = movieBox.query().filter(new QueryFilter<Movie>() {
#Override
public boolean keep(#NonNull Movie entity) {
return entity.getGenres().contains(genreSciFi);
}
}).build().find();
To make the contains-Method work correctly, override equals-Method in your Genre-Entity:
#Override
public boolean equals(Object obj) {
return obj instanceof Genre && ((Genre) obj).getId() == id && ((Genre) obj).getName().equals(name);
}
Unfortunately, this part of the API is not exposed in Java yet. We want to refactor the Query API very soon.
Until this is ready, you can workaround using query filtering. Example using Java/Kotlin-ish code for brevity:
Query query = movieBox.query().filter(movie -> {
return genres.contains(genre -> {
return "Sci-Fi".equals(genre.getName())
}
}).build()
(Will make it similar in Java with the next update.)

Nested json structure

I want to create a dynamodb which has following features
PK: orderId
RK: date
shipped: Y|N
details: <nested json structure>
Point 4 is the one which i am really confused about. If i keep details field as a string and try to store json as string, AWS escape " characters i.e., {"onlineStore" : "283"} becomes {\"onlineStore\": \"283\"}
This get's retrieved properly from dynamodb with details as string mappings but if i have to convert it to a pojo using jackson, I have to take care of those \.
So as an alternative, I thought that i could create details a POJO i.e.,
public class OrderDetail{
private int onlineStore;
// rest of the JSON properties
#JsonCreator
public OrderDetail (#JsonProperty("onlineStore") int onlineStore, ...){
this.onlineStore = onlineStore;
}
}
With the above implementation, i get error that DynamoDBMappingException: Couldn't convert attribte.
The OrderDetail type is a common type which is being used between my JSON REST Response as well so i want to avoid putting DynamoDB specific annotation here.
Now the question is what should be proper way to implement it.
If you are using DynamoDB Mapper class to perform the CRUD operation, you can use the annotation #DynamoDBTypeConvertedJson to save the order details.
DynamoDBTypeConvertedJson - Check this link for more details
DynamoDBMapper class:-
The AWS SDK for Java provides a DynamoDBMapper class, allowing you to
map your client-side classes to DynamoDB tables. To use
DynamoDBMapper, you define the relationship between items in a
DynamoDB table and their corresponding object instances in your code.
The DynamoDBMapper class enables you to access your tables, perform
various create, read, update and delete (CRUD) operations, and execute
queries.
Sample Implementation:-
#DynamoDBTable(tableName = "Order")
public class Order implements Serializable {
private static final long serialVersionUID = -3534650012619938612L;
private String orderId;
private OrderDetail orderDetail;
#DynamoDBHashKey(attributeName = "orderId")
#DynamoDBAutoGeneratedKey
public String getOrderId() {
return orderId;
}
public void setOrderId(String orderId) {
this.orderId = orderId;
}
#DynamoDBTypeConvertedJson
public OrderDetail getOrderDetail() {
return orderDetail;
}
public void setOrderDetail(OrderDetail orderDetail) {
this.orderDetail = orderDetail;
}
}
public class OrderDetail implements Serializable {
private static final long serialVersionUID = 7312390212027563305L;
private Integer onlineStore;
public Integer getOnlineStore() {
return onlineStore;
}
public void setOnlineStore(Integer onlineStore) {
this.onlineStore = onlineStore;
}
#Override
public String toString() {
return "OrderDetail [onlineStore=" + onlineStore + "]";
}
}
public Order loadOrder(String orderId) {
DynamoDBMapper dynamoDBMapper = new DynamoDBMapper(dynamoDBClient);
Order order = dynamoDBMapper.load(Order.class, orderId,
new DynamoDBMapperConfig(DynamoDBMapperConfig.ConsistentReads.CONSISTENT));
System.out.println("Order : " + order.toString());
System.out.println("Order Id : " + order.getOrderId());
System.out.println("Order Detail : " + order.getOrderDetail());
System.out.println("Online store : " + order.getOrderDetail().getOnlineStore());
return order;
}
Output:-
Order Id : 0beced28-f1de-4c44-8094-6de687d25e97
Order Detail : OrderDetail [onlineStore=1]
Online store : 1
Data in DDB:-
As you mentioned, the order detail will be stored with escape characters. However, when you get the data using DynamoDB mapper, it will be in deserialized form (i.e. as POJO object).

Trying to use SQL Function in hibernate

I am trying to call My-SQL function which is returning calculated value based on input parameters. I am using native queries for this purpose, I am able to get all fields except calculated field. I am always getting NULL as value for calculated field. Moreover If I execute same query in SQL Client, it gives proper result.
Test.class
#NamedNativeQueries({
#NamedNativeQuery(
name = "getTestData",
query = "Select test_id, BillType, Description, Material, Netvalue1, "
+ "NetValue(billType, Netvalue1) as Sales_Rs "
+ "from test1",
resultClass = Test.class
)
})
#Entity
#Table(name="TEST1")
public class Test {
private static final long serialVersionUID = 1L;
#Id
#GeneratedValue
#Column(name="TEST_ID")
private Integer test_id;
#Column(name="Billtype")
private String Billtype;
#Column(name="Description")
private String Description;
#Column(name="Material")
private String Material;
#Column(name="Netvalue1")
private Double Netvalue1;
#Transient
private Double Sales_Rs;
// getters and setters
.
.
.
};
Here is how I am calling native query:
#SuppressWarnings("unchecked")
#Override
public List<Test> getAllTestData() throws MyAppException {
List<Test> result;
try {
Session session = sessionFactory.getCurrentSession();
Query query = session.getNamedQuery("getTestData");
result = query.list();
} catch (DataAccessException e) {
throw new MyAppException("Could not add a new record :", e);
}
return result;
}
Here is Stored function:
CREATE FUNCTION NetValue(billType CHAR(30), Netvalue1 DOUBLE) RETURNS double
BEGIN
Declare RetValue DOUBLE;
SET RetValue =
CASE billType
WHEN 'A' THEN 0.10 * Netvalue1
WHEN 'B' THEN 0.05 * Netvalue1
WHEN 'C' THEN 0.025 * Netvalue1
ELSE Netvalue1
END;
RETURN RetValue;
END;
You declared field Double Sales_Rs as transient, therefore it is not handled by Hibernate.
See this thread for two solutions:
a) Use a Hibernate specific mapping to calculate Sales_RS by a formula which calls your database function:
#Formula("NetValue(billType, Netvalue1)")
private Double Sales_Rs;
b) use the JPA #Postload annotation to calculate Sales_RS after the object has been loaded:
#Transient
private Double Sales_Rs;
#PostLoad
private void onLoad() {
Sales_Rs = ... // same logic as in your db function
}
In both cases you can drop the native query and use simple hql:
#NamedQueries({
#NamedQuery(
name = "getTestData",
query = "from Test"
)})

How to build a Morphia query on a subset of the properties of a Java Collection's elements?

I'm not being able to query a MongoDB document according to field values of an embedded Java Collection.
I have the following entity:
#Entity
public class StationHistoryEntry // extends ...
{
#Embedded
private Set<SongFeedback> songFeedback = new HashSet<SongFeedback>();
// ...
}
And the following embedded class:
#Embedded
public class SongFeedback // extends ...
{
#Embedded
private FeedbackType feedbackType;
private ObjectId userId;
public enum FeedbackType {
THUMBS_UP, THUMBS_DOWN, STAR;
}
// other properties
}
What I need to do is to find StationHistoryEntries that have SongFeedback with a given userId and feedbackType=STAR.
I've tried the following but didn't succeed when the other SongFeedback properties (the ones not shown on the code snippet because I don't have control over their values) were not null, which happens in production:
public List<StationHistoryEntry> findStarredByUserId(ObjectId userId) {
SongFeedback songFeedback = new SongFeedback(FeedbackType.STAR, userId);
return ds.find(StationHistoryEntry.class)
.filter("songFeedback elem", songFeedback).asList();
}
And I've also tried the following, but it always returns an empty list:
public List<StationHistoryEntry> findStarredByUserId(ObjectId userId) {
Query<StationHistoryEntry> query = ds.createQuery(StationHistoryEntry.class);
query.and(
query.criteria("songFeedback.userId").equal(userId),
query.criteria("songFeedback.feedbackType").equal(FeedbackType.STAR));
return query.asList();
}
If it helps at all, I've created a Github repository with the stripped down code and a unit test: https://github.com/gabrielcs/MorphiaQueryStackOverflow
Any ideas? Thanks!
try this
public List<StationHistoryEntry> findStarredByUserId(ObjectId userId) {
Query<StationHistoryEntry> query = ds.createQuery(StationHistoryEntry.class);
query.and(
query.criteria("songFeedback.userId").equal(userId),
query.criteria("songFeedback.feedbackType").in(FeedbackType.STAR));
return query.asList();
}

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