Hi all,
The java code below is from mkyong's 1 to 1 example. I see the stock object has a stock detail object and
also the stock detail object has a stock object. So, this enables the 1 to 1 relationship of the database's
stock and stock details tables.
But, what is the reasoning for setting up the java code this way? Isn't this duplication? Does this relationship
have to be bidirectional? If we did not have persistence would we still set up the java code as such?
thanks,
m.
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stock.java
Code:
package com.mkyong.stock;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import static javax.persistence.GenerationType.IDENTITY;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;
@Entity
@Table(name = "stock", catalog = "mkyongdb", uniqueConstraints = {
@UniqueConstraint(columnNames = "STOCK_NAME"),
@UniqueConstraint(columnNames = "STOCK_CODE") })
public class Stock implements java.io.Serializable {
private Integer stockId;
private String stockCode;
private String stockName;
private StockDetail stockDetail;
public Stock() {
}
public Stock(String stockCode, String stockName) {
this.stockCode = stockCode;
this.stockName = stockName;
}
public Stock(String stockCode, String stockName, StockDetail stockDetail) {
this.stockCode = stockCode;
this.stockName = stockName;
this.stockDetail = stockDetail;
}
@Id
@GeneratedValue(strategy = IDENTITY)
@Column(name = "STOCK_ID", unique = true, nullable = false)
public Integer getStockId() {
return this.stockId;
}
public void setStockId(Integer stockId) {
this.stockId = stockId;
}
@Column(name = "STOCK_CODE", unique = true, nullable = false, length = 10)
public String getStockCode() {
return this.stockCode;
}
public void setStockCode(String stockCode) {
this.stockCode = stockCode;
}
@Column(name = "STOCK_NAME", unique = true, nullable = false, length = 20)
public String getStockName() {
return this.stockName;
}
public void setStockName(String stockName) {
this.stockName = stockName;
}
@OneToOne(fetch = FetchType.LAZY, mappedBy = "stock", cascade = CascadeType.ALL)
public StockDetail getStockDetail() {
return this.stockDetail;
}
public void setStockDetail(StockDetail stockDetail) {
this.stockDetail = stockDetail;
}
}
---------------------------------------------------------------------------------------------------------------------------------------------------
stockdetail.java
Code:
package com.mkyong.stock;
import java.util.Date;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.FetchType;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.PrimaryKeyJoinColumn;
import javax.persistence.Table;
import javax.persistence.Temporal;
import javax.persistence.TemporalType;
import org.hibernate.annotations.GenericGenerator;
import org.hibernate.annotations.Parameter;
@Entity
@Table(name = "stock_detail", catalog = "mkyongdb")
public class StockDetail implements java.io.Serializable {
private Integer stockId;
private Stock stock;
private String compName;
private String compDesc;
private String remark;
private Date listedDate;
public StockDetail() {
}
public StockDetail(Stock stock, String compName, String compDesc,
String remark, Date listedDate) {
this.stock = stock;
this.compName = compName;
this.compDesc = compDesc;
this.remark = remark;
this.listedDate = listedDate;
}
@GenericGenerator(name = "generator", strategy = "foreign",
parameters = @Parameter(name = "property", value = "stock"))
@Id
@GeneratedValue(generator = "generator")
@Column(name = "STOCK_ID", unique = true, nullable = false)
public Integer getStockId() {
return this.stockId;
}
public void setStockId(Integer stockId) {
this.stockId = stockId;
}
@OneToOne(fetch = FetchType.LAZY)
@PrimaryKeyJoinColumn
public Stock getStock() {
return this.stock;
}
public void setStock(Stock stock) {
this.stock = stock;
}
@Column(name = "COMP_NAME", nullable = false, length = 100)
public String getCompName() {
return this.compName;
}
public void setCompName(String compName) {
this.compName = compName;
}
@Column(name = "COMP_DESC", nullable = false)
public String getCompDesc() {
return this.compDesc;
}
public void setCompDesc(String compDesc) {
this.compDesc = compDesc;
}
@Column(name = "REMARK", nullable = false)
public String getRemark() {
return this.remark;
}
public void setRemark(String remark) {
this.remark = remark;
}
@Temporal(TemporalType.DATE)
@Column(name = "LISTED_DATE", nullable = false, length = 10)
public Date getListedDate() {
return this.listedDate;
}
public void setListedDate(Date listedDate) {
this.listedDate = listedDate;
}
}
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