Patel Posts - Answer Overflow

Patel

•Created by Patel on 6/24/2024 in #java-help

How to combine results from two table with same columns and return the result in Page

For example I've two tables Order1 and Order2 . Now I want to create one GET API name wih /getCombinedOrders which will return the result from Order1 and Order2 in page format.

@Entity
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Order1 {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private String id;

    @Column(name = "QUANTITY")
    private String quantity;

    @Column(name = "PRODUCT_NAME")
    private String productName;

    @Column(name = "ORDER_DATE")
    private Instant orderDate;

    @Column(name = "STATUS")
    private String orderStatus;

    @Column(name = "TOTAL_AMOUNT")
    private long amount;
}

@Entity
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Order2 {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private String id;

    @Column(name = "QUANTITY")
    private String quantity;

    @Column(name = "PRODUCT_NAME")
    private String productName;

    @Column(name = "ORDER_DATE")
    private Instant orderDate;

    @Column(name = "STATUS")
    private String orderStatus;

    @Column(name = "TOTAL_AMOUNT")
    private long amount;
}

@Entity
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Order1 {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private String id;

    @Column(name = "QUANTITY")
    private String quantity;

    @Column(name = "PRODUCT_NAME")
    private String productName;

    @Column(name = "ORDER_DATE")
    private Instant orderDate;

    @Column(name = "STATUS")
    private String orderStatus;

    @Column(name = "TOTAL_AMOUNT")
    private long amount;
}

@Entity
@Data
@Builder
@AllArgsConstructor
@NoArgsConstructor
public class Order2 {
    @Id
    @GeneratedValue(strategy = GenerationType.UUID)
    private String id;

    @Column(name = "QUANTITY")
    private String quantity;

    @Column(name = "PRODUCT_NAME")
    private String productName;

    @Column(name = "ORDER_DATE")
    private Instant orderDate;

    @Column(name = "STATUS")
    private String orderStatus;

    @Column(name = "TOTAL_AMOUNT")
    private long amount;
}

Strategies I tried: I've tried to get the data from Order1 repository and Order2 repository and return the result in Page. This strategy has some drawbacks regarding the Pagination. In this strategy if user pass pageSize 10 then we need to divide it into half and fetch 5 orders from each table combine and return but these is issue if one table has only 2 order left and another table still have 20 orders then our response will be only 7 orders. 2nd strategy will fetch all the data from both table, create list and sort and return but in this approach we negligent the use of Pagination that we do not need to fetch thousand of record for 10 rows on user screen. Could you please help me on this?

4 replies

JCHJava Community | Help. Code. Learn.

•Created by Patel on 1/13/2024 in #java-help

Couldn't understand why 1<1 become true in following code?

I'm solving one of the basic recursion question from coding website. I need to assign 1 to n inside array, so platform will print the array. Here is the link of question: https://www.codingninjas.com/studio/problems/print-1-to-n_628290?leftPanelTabValue=PROBLEM Here is my solution for the platform:

public class Solution {
    public static int[] printNos(int x) {
        int[] arr = new int[x];
        recursiveFunc(arr, x);
        return arr;
    }


    public static void recursiveFunc(int[] arr, int n){
        if(n<1){
            return;
        }
        arr[n-1] = n;
        recursiveFunc(arr, n-1);
    }
}

public class Solution {
    public static int[] printNos(int x) {
        int[] arr = new int[x];
        recursiveFunc(arr, x);
        return arr;
    }


    public static void recursiveFunc(int[] arr, int n){
        if(n<1){
            return;
        }
        arr[n-1] = n;
        recursiveFunc(arr, n-1);
    }
}

And if you want to try in your IDE, you can try the following code:

package Recursion;

public class OneToN {
    public static int[] printNos(int x) {
        int[] arr = new int[x];
        recursiveFunc(arr, x);
        return arr;
    }
    public static void recursiveFunc(int[] arr, int n){
        System.out.println("Nth value: " + n);
        boolean result = n<1;
        System.out.println("n<1: " + result);
        if(n<1){
            return;
        }
        arr[n-1] = n;
        recursiveFunc(arr, n-1);
    }
}

package Recursion;

public class OneToN {
    public static int[] printNos(int x) {
        int[] arr = new int[x];
        recursiveFunc(arr, x);
        return arr;
    }
    public static void recursiveFunc(int[] arr, int n){
        System.out.println("Nth value: " + n);
        boolean result = n<1;
        System.out.println("n<1: " + result);
        if(n<1){
            return;
        }
        arr[n-1] = n;
        recursiveFunc(arr, n-1);
    }
}

Main.java:

public class Main {
        public static void main(String[] args) {
            System.out.println(Arrays.toString(OneToN.printNos(5)));
        }
    }

public class Main {
        public static void main(String[] args) {
            System.out.println(Arrays.toString(OneToN.printNos(5)));
        }
    }

13 replies

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