I'm working on setting up a DAO for Cassandra in spring.
Now I have a question regarding using composite classes multiple times in an object.
I have this class Setting:
#Table(value = "settings")
public class Setting {
#PrimaryKey
private User owner;
#Column("key")
private String key;
#Column("value")
private String value;
#Column("updated_by")
private User updatedBy;
}
And the class User:
#PrimaryKeyClass
public class User implements Serializable{
#PrimaryKeyColumn(name = "userId", ordinal = 0, type = PrimaryKeyType.PARTITIONED)
private String id;
#PrimaryKeyColumn(name = "userIdType", ordinal = 1, type = PrimaryKeyType.PARTITIONED)
private String idType;
}
So I'm using the class User twice. Once as primary key "owner" and once as "updatedBy".
When using this in the CassandraOperations classes, it works fine as the primary key, but not again as another column.
It complains about column name userId already being used. Makes sense.
So how can I make this work?
I could use UserDefined Types perhaps?
CREATE TYPE test_keyspace.user (
id text,
id_type text
);
But how can I do that from java Annotations?
Or, how can I reuse the same class otherwise?
Considering the relatively simple data structures in Cassandra, I am ok with flattening the User class as a single String like idType.id too.
Thanks for any help!
Ok, found it here, answered by denzal.
My classes now look like:
#Table("settings")
public class Setting {
#PrimaryKeyColumn(name = "owner", ordinal = 0, type = PrimaryKeyType.PARTITIONED)
#CassandraType(type = DataType.Name.UDT, userTypeName = "user_type")
private User owner;
#PrimaryKeyColumn(name = "key", ordinal = 1, type = PrimaryKeyType.CLUSTERED)
#CassandraType(type = DataType.Name.TEXT)
private String key;
#CassandraType(type = DataType.Name.TEXT)
private String value;
#CassandraType(type = DataType.Name.UDT, userTypeName = "user_type")
private User lastUpdatedBy;
}
And User Class:
#UserDefinedType("user_type")
public class User implements Serializable{
#CassandraType(type = DataType.Name.TEXT)
private String id;
#CassandraType(type = DataType.Name.TEXT)
private IdType idType;
}
Works nicely.
Related
What I have setup are two tables, one for a user created account, and the other that lets the user buy a product.
I have both tables set up like so
Customer Table
#PrimaryKey(autoGenerate = true)
private int custId;
#ColumnInfo(name = "user_name")
private String userName;
#ColumnInfo(name = "password")
private String password;
#ColumnInfo(name = "first_name")
private String firstName;
#ColumnInfo(name = "last_name")
private String lastName;
#ColumnInfo(name = "address")
private String address;
#ColumnInfo(name = "city")
private String city;
#ColumnInfo(name = "postal_code")
private String postalCode;
#ColumnInfo(name = "country")
private String country;
Phone Table
#PrimaryKey(autoGenerate = true)
private int productId;
private String phoneMake;
private String phoneModel;
private String phoneColor;
private String storageCapacity;
private Float price;
What I have set up are two foreign keys, one in each table. My last table is for ordering the phones, which requires using both Primary Keys from each table. What I feel like I need is a ForeignKey, similar in vein to the PrimaryKey already created. The problem is that I am unsure how to implement that into the program. Everything I try doing is not working. I have looked at the documentation, but nothing clicks. I hope you can help me with the correct screenshot. If more is needed let me know (This code is written in Java code)
If you simply want a Customer to have 1 phone, then you have have a single column (member variable) for the relationship that will store the phone's product id.
e.g.
private int mapToPhone; //<<<<< ADDED no need for #ColumnInfo the column name will be as per the variable name.
Obviously you set the value to an appropriate value.
To then get the Customer with the phone's details then you have a POJO that embeds the parent (Customer) using the #Embedded annotation has the child (Phone) using the #Relation annotation.
e.g. :-
class CustomerWithPhoneDetails {
#Embedded
Customer customer;
#Relation(
entity = Phone.class,
parentColumn = "mapToPhone",
entityColumn = "productId"
)
Phone phoneDetails;
}
You can then have a method in the #Dao annotated interface/abstract class which queries the parent table BUT returns the POJO or list/array of the POJO e.g. :-
#Query("SELECT * FROM Customer")
abstract List<CustomerWithPhoneDetails> getAllCustomersWithPhoneDeytails();
Example
Based upon your code, and the additional example code along with an #Database annotated abstract class :-
#Database(entities = {Customer.class,Phone.class}, version = 1, exportSchema = false)
abstract class TheDatabase extends RoomDatabase {
abstract AllDao getAllDao();
private static volatile TheDatabase instance = null;
public static TheDatabase getInstance(Context context) {
if (instance == null) {
instance = Room.databaseBuilder(context,TheDatabase.class,"the_database.db")
.allowMainThreadQueries()
.build();
}
return instance;
}
}
and an Activity e.g. :-
public class MainActivity extends AppCompatActivity {
TheDatabase db;
AllDao dao;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = TheDatabase.getInstance(this);
dao = db.getAllDao();
long phone01ProductId = dao.insert(new Phone("PhoneMaker001","Model001","Color001","100Mb",111.11F));
long phone02ProductId = dao.insert(new Phone("PhoneMaker002","Model002","Color002","200Mb",222.22F));
dao.insert(new Customer("c001","password001","firstname001","lastname001","address001","city001","country001","postcode001",(int) phone01ProductId));
dao.insert(new Customer("c002","password002","firstname002","lastname002","address002","city002","country002","postcode002",(int) phone02ProductId));
for(CustomerWithPhoneDetails cwpd: dao.getAllCustomersWithPhoneDeytails()) {
Log.d("DBINFO","Customer is " + cwpd.customer.getUserName() + " etc. Phone is " + cwpd.phoneDetails.getProductId() + " etc." );
}
}
}
Note that suitable constructors have been coded in both the Phone and Customer class (default/empty constructor and one, annotated with #Ignore annotation that allows all values bar the id to be passed as used in the example below)
Note that ideally long rather than int should be used for the id columns.
Results
The Log :-
D/DBINFO: Customer is c001 etc. Phone is 1 etc.
D/DBINFO: Customer is c002 etc. Phone is 2 etc.
App Inspection :-
and :-
I like to store a object like:
#Table(value = "my_table")
public class MyTableDto {
#PrimaryKeyColumn(name = "uid", type = PrimaryKeyType.PARTITIONED)
#CassandraType(type = DataType.Name.UUID)
private UUID uid;
#Column(value = "child_ids")
private List<ChildIdDto> childIds;
}
Then I get the exception:
Caused by: org.springframework.dao.InvalidDataAccessApiUsageException: Only primitive types are allowed inside Collections for property [childIds] of type ['interface java.util.List'] in entity [de.myapplication.repository.dto.MyTableDto]
I do understand the exception, but is there another way to persist custom objects?
EDIT:
When I comment out this attribute, everything works
! Never say never, I got the solution.
To give a good example, I will list all according classes.
ParentClass.java
#Table(value = "my_table") //OPT
public class MyTableDto {
#PrimaryKeyColumn(name = "uid", type = PrimaryKeyType.PARTITIONED)
#CassandraType(type = DataType.Name.UUID)
private UUID uid;
#Column(value = "child_ids") //OPT
private List<ChildDto> childIds;
}
ChildDto.java
#UserDefinedType // THE SOLUTION
public class ChildDto {
#Column(value = "child") //OPT
#CassandraType(type = DataType.Name.TEXT) //OPT
private String groupId;
#Column(value = "description") //OPT
#CassandraType(type = Name.TEXT) //OPT
private String description;
}
The #UserDefinedType is the solution.
For more information see here.
NOTE: Each annotation with "OPT" is NOT required
I am using hibernate 4. I am writing a filter. The strange thing I noticed is the filter is not getting applied if I use session.get() method
public SecurityAgency getSecurityAgencyById(int id) {
Session session = this.sessionFactory.getCurrentSession();
session.enableFilter("byEnabled");
SecurityAgency s = (SecurityAgency)session.get(SecurityAgency.class, new Integer(id));
return s;
}
Filter starts working as soon as I replace the session.get method with session.createQuery method and send a HQL query. I am unable to find any reason for this behaviour in the hibernate documentation.
FIlter declaration in securtiy agency class
#Entity
#Table(name="security_agency")
public class SecurityAgency implements java.io.Serializable {
#Id
#Column(name = "id")
#GeneratedValue(strategy = GenerationType.IDENTITY)
private int id;
#Column(name="name")
private String name;
#Column(name="code")
private String code;
#Column(name="website")
private String website;
#Column(name="tan")
private String tan;
#Column(name="email")
private String email;
#Column(name="pan")
private String pan;
#Column(name="created_at")
private Date createdAt;
#Column(name="created_by")
private long createdBy;
#Column(name="modified_at")
private Date modifiedAt;
#Column(name="modified_by")
private long modifiedBy;
#OneToMany(mappedBy="securityAgency",fetch = FetchType.EAGER)
#JsonIgnoreProperties("securityAgency")
#Filter(name = "byEnabled", condition = "is_enabled= 1")
private Set<ContactPerson> contactPersons = new HashSet<ContactPerson>(0);
public SecurityAgency() {
}
Contact person class
#Entity
#Table(name = "contact_person")
#FilterDefs({
#FilterDef(name="byEnabled"),
#FilterDef(name="bySecurityAgency",parameters = #ParamDef(name="agency_id", type="int"))
})
#Filters({
#Filter(name="byEnabled", condition = "is_enabled = 1"),
#Filter(name="bySecurityAgency", condition = "agency_id= :agency_id ")
})
public class ContactPerson implements java.io.Serializable {
Filter doesn't work if you are fetching using id value.Use Query interface instead. See this thread
if you want to use table column values you need to use filter join table ( #FilterJoinTable ), #Filter is applied to target entity rather than table
try,
#FilterJoinTable(name = "byEnabled", condition = "is_enabled= :enabled")
private Set<ContactPerson> contactPersons = new HashSet<ContactPerson>(0);
get
session.enableFilter("byEnabled").setParameter("enabled", Integer.valueOf(1));
I have created custom defined types in cassandra and I'm trying to insert the data using spring. At first i thought using entity like this would work:
#PrimaryKeyColumn(name = "appid", ordinal = 0, type = PrimaryKeyType.PARTITIONED)
private String appid;
#PrimaryKeyColumn(name = "event", ordinal = 1, type = PrimaryKeyType.PARTITIONED, ordering = Ordering.ASCENDING)
private String event;
#PrimaryKeyColumn(name = "date", ordinal = 2, type = PrimaryKeyType.CLUSTERED, ordering = Ordering.DESCENDING)
private Date date;
#PrimaryKeyColumn(name = "userid", ordinal = 3, type = PrimaryKeyType.PARTITIONED)
private String userid;
#Column (name = "items")
#Frozen
private Map<CassandraEventParamModel,CassandraEventStatsModel> items;
And created a UDT in java like this (param from create type):
#UDT(keyspace = "ms_analytics", name = "param")
public class CassandraEventParamModel {
#Field(name = "key")
public String key;
#Field(name = "value")
public String value;
but I kept getting an error which says
Invocation of init method failed; nested exception is org.springframework.data.cassandra.mapping.VerifierMappingExceptions:
Cassandra entities must have the #Table, #Persistent or #PrimaryKeyClass Annotation
I wonder what is the proper way to deliver data using spring-data into cassandra.
Thanks
I am using Hibernate custom user type to map enum to a table varchar/char. I am using custom user type code from here (https://community.jboss.org/wiki/Java5StringValuedEnumUserType). I am trying following annotation to do the mapping but its not working.
#Transient
#Type(type = "data.model.base.StringValuedEnumType", parameters = {
#Parameter(name = "enumClass", value = "data.common.TypeEnum"),
#Parameter(name = "identifierMethod", value = "dbCode") })
private TypeEnum typeEnum;
TypeEnum code:
public enum TypeEnum implements StringValuedEnum {
OFF("OFF", "O"),
ON("ON, "O"),
private String dbCode;
private String desc;
TypeEnum(String desc, String dbCode) {
this.desc=desc;
this.dbCode = dbCode;
}
#Override
public String dbCode() {
return dbCode;
}
public String desc() {
return desc;
}
}
I believe I am doing something wrong in the annotation but I am not able to figure out what is it. Any idea anyone?
I have found it. I updated the annotation by removing #Transient and adding in a #Column for the mapping. I also updated the code to take care of the passed name and removed defaultValue.
#Column(name = "TYP_CD", length = 1)
#Type(type = "data.model.base.StringValuedEnumType", parameters = {
#Parameter(name = "enumClass", value = "data.common.TypeEnum")})
private TypeEnum typeEnum;