java - How to get ID from db using EntityManager? -


using entity manager how id of row database 1 of column value true , update row. db structure this:

id   employees  start_time  end_time  monday    tuesday     wednessday      thursday    friday   saturday  sunday 1       5          1.0        7.0     true      false       false            false      false     false     false

how id of row has monday: false , rest of days true , after getting id update row.

in sql id similar this:

select id  histogram  monday = true  , tueday = false  , wednessday = false  , thursday = false  , friday = false  , saturday = false  , sunday = false ;

this model class:

import java.io.serializable; import javax.persistence.column; import javax.persistence.entity; import javax.persistence.generatedvalue; import javax.persistence.generationtype; import javax.persistence.id; import javax.persistence.table; import javax.validation.constraints.notnull; import javax.validation.constraints.size;  import org.springframework.stereotype.component;   @entity @table(name = "histogram") public class histogram implements serializable {      private long id;     private int employees;     private double starttime;      private double endtime;      private boolean monday;     private boolean tuesday;     private boolean wednessday;     private boolean thursday;     private boolean friday;     private boolean saturday;     private boolean sunday;      public histogram() {     }      public histogram(int employees, double starttime, double endtime, boolean monday, boolean tuesday,             boolean wednessday, boolean thursday, boolean friday, boolean saturday, boolean sunday) {         this.employees = employees;         this.starttime = starttime;         this.endtime = endtime;         this.monday = monday;         this.tuesday = tuesday;         this.wednessday = wednessday;         this.thursday = thursday;         this.friday = friday;         this.saturday = saturday;         this.sunday = sunday;     }      @id     @generatedvalue(strategy = generationtype.auto)     public long getid() {         return id;     }       public void setid(long id) {         this.id = id;     }      //@size(min = 2, max = 255, message = "enter between 2 , 255 characters!")     @column(name = "employees")     @notnull     public int getemployees() {         return employees;     }      public void setemployees(int employees) {         this.employees = employees;     }      @column(name = "starttime")     @notnull     public double getstarttime() {         return starttime;     }      public void setstarttime(double starttime) {         this.starttime = starttime;     }      @column(name = "endtime")     @notnull     public double getendtime() {         return endtime;     }      public void setendtime(double endtime) {         this.endtime = endtime;     }      @column(name = "monday")     @notnull     public boolean ismonday() {         return monday;     }      public void setmonday(boolean monday) {         this.monday = monday;     }      @column(name = "tuesday")     @notnull     public boolean istuesday() {         return tuesday;     }      public void settuesday(boolean tuesday) {         this.tuesday = tuesday;     }      @column(name = "wednessday")     @notnull     public boolean iswednessday() {         return wednessday;     }      public void setwednessday(boolean wednessday) {         this.wednessday = wednessday;     }      @column(name = "thursday")     @notnull     public boolean isthursday() {         return thursday;     }      public void setthursday(boolean thursday) {         this.thursday = thursday;     }      @column(name = "friday")     @notnull     public boolean isfriday() {         return friday;     }      public void setfriday(boolean friday) {         this.friday = friday;     }      @column(name = "saturday")     @notnull     public boolean issaturday() {         return saturday;     }      public void setsaturday(boolean saturday) {         this.saturday = saturday;     }      @column(name = "sunday")     @notnull     public boolean issunday() {         return sunday;     }      public void setsunday(boolean sunday) {         this.sunday = sunday;     }  }

this dao:

import javax.persistence.entitymanager; import javax.persistence.persistencecontext; import javax.persistence.criteria.criteriabuilder; import javax.persistence.criteria.criteriaquery; import javax.persistence.criteria.parameterexpression; import javax.persistence.criteria.root;  import org.springframework.stereotype.repository;  /**  * @author junaid khalid  *  */ @repository public class histogramdao {  @persistencecontext  private entitymanager entitymanager;    public void create(histogram histogram) {  entitymanager.persist(histogram);  }    public void update(histogram histogram) {  entitymanager.merge(histogram);  }    public histogram getbesoinrequestbyid(long id) {  return entitymanager.find(histogram.class, id);  }    public void delete(long id) {  histogram histogram = getbesoinrequestbyid(id);  if (histogram != null) {  entitymanager.remove(histogram);  }  } }

this service class:

import org.springframework.beans.factory.annotation.autowired; import org.springframework.stereotype.component; import org.springframework.transaction.annotation.transactional;  /**  * @author junaid khalid  *  */ @component @transactional public class histogramservice {  @autowired  private histogramdao histogramdao;   public void create(histogram histogram) {      histogramdao.create(histogram);  }   public void update(histogram histogram) {      histogramdao.update(histogram);      }   public void delete(long id) {      histogramdao.delete(id);  } }

since familiar wih sql can use jpql find items criteria specified.

typedquery<long> query = entitymanager.createquery("select h.id histogram h h.monday = true , h.tuesday = false , h.wednessday = false , h.thursday = false , h.friday = false , h.saturday = false , h.sunday = false ");  list<long> histograms = query.getresultlist();

then use id retrieved histogram entity , apply changes

histogram histogram = entitymanager.find(histogram.class,histogramid); //changes on entity ... entitymanager.persist(histogram);

the other choice use criteria api.


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