我想添加一个过滤器来检查用户可能输入的重复值。我不确定我的查询中哪里出错。筛选重复值。
我的查询不进入循环检查名称是否已经存在。
我对google-could很新。如果有人能告诉我如何解决我的问题或者是否有更好的解决方案。
else if (commandEls[0].equals("add_director")) {
String name = commandEls[1];
String gender = commandEls[2];
String date_of_birth = commandEls[3];
boolean duplicate = false;
//add a director record with the given fields to the datastore, don't forget to check for duplicates
Entity addDirectorEntity = new Entity("Director");
// check if the entity already exits
// if !duplicate add, else "Already exisits"
Query directorExists = new Query("Movies");
// Director Name is the primary key
directorExists.addFilter("directorName",Query.FilterOperator.EQUAL, name);
System.out.print(name);
PreparedQuery preparedDirectorQuery = datastore.prepare(directorExists);
System.out.print("outside");
for(Entity directorResult : preparedDirectorQuery.asIterable()){
// result already exists in the database
String dName = (String) directorResult.getProperty(name);
System.out.print(dName);
System.out.print("finish");
duplicate = true;
}
if(!duplicate){
addDirectorEntity.setProperty("directorName",name);
addDirectorEntity.setProperty("directorGender",gender);
addDirectorEntity.setProperty("directorDOB",date_of_birth);
try{
datastore.put(addDirectorEntity);
results = "Command executed successfully!";
}
catch(Exception e){
results = "Error";
}
}
else {
results = "Director already exists!";
}
}