JPA 2从元模型中删除/插入订单
我试图使用JPA2元数据来确定从数据库中插入/删除行的顺序,这样约束就不会成为问题(稍后将在Java代码中使用)。这是使用JPA的备份/恢复方法的一部分 以下是我的方法:JPA 2从元模型中删除/插入订单,jpa,backup,metamodel,Jpa,Backup,Metamodel,我试图使用JPA2元数据来确定从数据库中插入/删除行的顺序,这样约束就不会成为问题(稍后将在Java代码中使用)。这是使用JPA的备份/恢复方法的一部分 以下是我的方法: 按关系/约束的数量对表进行分组(仅考虑一对多和一对一) 具有零实例的表(根据#1)可以添加/删除记录而不会出现问题 具有一个实例的表可以添加/删除记录,只要相关表已“就绪” Ready通过Ready,我的意思是填充其所有相关的表记录,以便外键对插入有效,或者没有其他表引用此表中的记录 我确信这将是某种递归方法,但我被卡住了。任
/**
* Get the execution order from the EntityManager meta data model.
*
* This will fail if the EntityManager is not JP2 compliant
* @param em EntityManager to get the metadata from
* @return ArrayList containing the order to process tables
*/
protected static ArrayList<String> getProcessingOrder(EntityManager em) {
ArrayList<String> tables = new ArrayList<String>();
//This holds the amount of relationships and the tables with that same amount
HashMap<Integer, ArrayList<String>> tableStats = new HashMap<Integer, ArrayList<String>>();
//This holds the table and the tables referenced by it
HashMap<String, ArrayList<String>> references = new HashMap<String, ArrayList<String>>();
for (EntityType et : em.getMetamodel().getEntities()) {
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER, et.getName());
int amount = 0;
Iterator<SingularAttribute> sIterator = et.getSingularAttributes().iterator();
while (sIterator.hasNext()) {
SingularAttribute next = sIterator.next();
switch (next.getPersistentAttributeType()) {
case BASIC:
case ELEMENT_COLLECTION:
case EMBEDDED:
case ONE_TO_MANY:
case ONE_TO_ONE:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,
"Ignoring: {0}", next.getName());
break;
case MANY_TO_MANY:
case MANY_TO_ONE:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO,
"{3} has a {2} relationship: {0} with: {1}",
new Object[]{next.getName(), next.getBindableJavaType(),
next.getPersistentAttributeType().name(), et.getName()});
if (!references.containsKey(et.getName())) {
references.put(et.getName(), new ArrayList<String>());
}
references.get(et.getName()).add(next.getBindableJavaType().getSimpleName());
amount++;
break;
default:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.SEVERE,
"Unexpected value: {0}", next.getName());
break;
}
}
Iterator<PluralAttribute> pIterator = et.getPluralAttributes().iterator();
while (pIterator.hasNext()) {
PluralAttribute next = pIterator.next();
switch (next.getPersistentAttributeType()) {
case BASIC:
case ELEMENT_COLLECTION:
case EMBEDDED:
case ONE_TO_MANY:
case MANY_TO_MANY:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,
"Ignoring: {0}", next.getName());
break;
case MANY_TO_ONE:
case ONE_TO_ONE:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO,
"{3} has a {2} relationship: {0} with: {1}",
new Object[]{next.getName(), next.getBindableJavaType(),
next.getPersistentAttributeType().name(), et.getName()});
if (!references.containsKey(et.getName())) {
references.put(et.getName(), new ArrayList<String>());
}
references.get(et.getName()).add(next.getBindableJavaType().getSimpleName());
amount++;
break;
default:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.SEVERE,
"Unexpected value: {0}", next.getName());
break;
}
}
if (!tableStats.containsKey(amount)) {
tableStats.put(amount, new ArrayList<String>());
}
tableStats.get(amount).add(et.getName());
}
Iterator<String> iterator = references.keySet().iterator();
while (iterator.hasNext()) {
String next = iterator.next();
Iterator<String> iterator1 = references.get(next).iterator();
StringBuilder refs = new StringBuilder();
while (iterator1.hasNext()) {
refs.append(iterator1.next()).append("\n");
}
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER, "References for {0}:\n{1}", new Object[]{next, refs.toString()});
}
//Need to sort entities with relationships even further
ArrayList<String> temp = new ArrayList<String>();
for (Entry<Integer, ArrayList<String>> e : tableStats.entrySet()) {
if (e.getKey() > 0) {
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO, "Tables with {0} references", e.getKey());
for (String t : e.getValue()) {
//Check the relationships of the tables
//Here's where I need help
boolean ready = true;
for (String ref : references.get(t)) {
if (!temp.contains(ref)) {
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO,
"{0} is not ready. Referenced table {1} is not ready yet", new Object[]{t, ref});
ready = false;
}
}
if (ready) {
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO, "{0} is ready.", t);
temp.add(t);
}
}
//-------------------------------------------------------
} else {
temp.addAll(e.getValue());
}
}
for (Entry<Integer, ArrayList<String>> e : tableStats.entrySet()) {
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,
"Amount of relationships: {0}", e.getKey());
StringBuilder list = new StringBuilder();
for (String t : e.getValue()) {
list.append(t).append("\n");
}
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER, list.toString());
}
tables.addAll(temp);
return tables;
}
/**
*从EntityManager元数据模型获取执行顺序。
*
*如果EntityManager不符合JP2,则此操作将失败
*@param em EntityManager从中获取元数据
*@return ArrayList包含处理表的顺序
*/
受保护的静态阵列列表getProcessingOrder(EntityManager em){
ArrayList tables=新的ArrayList();
//这将保存具有相同数量的关系和表的数量
HashMap tableStats=新HashMap();
//这将保存表及其引用的表
HashMap references=新的HashMap();
对于(EntityType et:em.getMetamodel().getEntities()){
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,et.getName());
整数金额=0;
迭代器sIterator=et.getSingularAttributes().Iterator();
while(sIterator.hasNext()){
SingularAttribute next=sIterator.next();
开关(next.getPersistentAttributeType()){
案例基础:
案例元素集合:
嵌入案例:
案例一对多:
案例一至案例一:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,
“忽略:{0}”,next.getName());
打破
案例多对多:
案例多对案例一:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO,
“{3}具有{2}关系:{0}与:{1}”,
新对象[]{next.getName(),next.getBindableJavaType(),
next.getPersistentAttributeType().name(),et.getName()});
如果(!references.containsKey(et.getName())){
references.put(et.getName(),newarraylist());
}
references.get(et.getName()).add(next.getBindableJavaType().getSimpleName());
金额++;
打破
违约:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.SEVERE,
“意外值:{0}”,next.getName());
打破
}
}
迭代器pIterator=et.getPluralAttributes().Iterator();
while(pIterator.hasNext()){
PluralAttribute next=pIterator.next();
开关(next.getPersistentAttributeType()){
案例基础:
案例元素集合:
嵌入案例:
案例一对多:
案例多对多:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,
“忽略:{0}”,next.getName());
打破
案例多对案例一:
案例一至案例一:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO,
“{3}具有{2}关系:{0}与:{1}”,
新对象[]{next.getName(),next.getBindableJavaType(),
next.getPersistentAttributeType().name(),et.getName()});
如果(!references.containsKey(et.getName())){
references.put(et.getName(),newarraylist());
}
references.get(et.getName()).add(next.getBindableJavaType().getSimpleName());
金额++;
打破
违约:
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.SEVERE,
“意外值:{0}”,next.getName());
打破
}
}
如果(!tableStats.containsKey(金额)){
tableStats.put(amount,new ArrayList());
}
get(amount).add(et.getName());
}
迭代器迭代器=references.keySet().Iterator();
while(iterator.hasNext()){
String next=迭代器.next();
迭代器迭代器1=references.get(next.Iterator();
StringBuilder refs=新的StringBuilder();
while(iterator1.hasNext()){
append(iterator1.next()).append(“\n”);
}
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.FINER,“对{0}:\n{1}的引用”,新对象[]{next,refs.toString()});
}
//需要进一步对具有关系的实体进行排序
ArrayList temp=新的ArrayList();
for(条目e:tableStats.entrySet()){
如果(如getKey()>0){
Logger.getLogger(XincoBackupManager.class.getSimpleName()).log(Level.INFO,“具有{0}个引用的表”,e.getKey());
for(字符串t:e.getValue()){
//检查表之间的关系
//这是我需要帮助的地方
布尔就绪=真;
for(字符串引用:references.get(t
// to get the tables
getTables(String catalog, String schemaPattern, String tableNamePattern, String[] types)
// to get the reference to the table
public ResultSet getExportedKeys(String catalog,
String schema,
String table)
throws SQLException