Hello!
There's an answer on stack overflow:
https://stackoverflow.com/questions/66716680/how-to-define-ignite-caches-for-objects-joined-from-multiple-tables/66764133#66764133
If you have further questions, you can ask here as well.
Regards,
--
Ilya Kasnacheev
сб, 20 мар. 2021 г. в 02:05, PunxsutawneyPhil3 <rwoodr...@niksun.com>:
> I am working with Postgres as an external persistent store Ignite and want
> to
> know the best way to define caches for objects who’s data is spread over
> multiple tables.
>
> E.G. for to work with this Person and Car class and their tables below, I
> have provided my own Implementation of the CacheStore. This approach seems
> to be very verbose however as I need to manually assign the field values
> myself. Are there any other methods I should be using to do this?
>
> public class PersonMO{
> private int id;
> private String name;
> private String address;
> private Set<Car> cars
>
> public PersonMO() {};
> public PersonMO(int id, String name, String address) {
> this.id = id;
> this.name = name;
> this.address = address;
> }
>
> public String getName() {
> return name;
> }
>
> public void setName(String name) {
> this.name = name;
> }
>
> public int getId() {
> return id;
> }
>
> public void setId(int id) {
> this.id = id;
> }
>
> public String getAddress() {
> return address;
> }
>
> public void setAddress(String address) {
> this.address = address;
> }
>
> public String toString() {
> return "ID: "+id +", Name: "+name+" AD: " +address;
> }
>
> public void setCars(Set<Car> cars) {
> this.cars = cars;
> }
>
> public Set<Car> getCars() {
> return cars;
> }
> }
>
> public class Car {
> int id;
> private String name;
>
> public Car(int id, String name) {
> this.id = id;
> this.name = name;
> }
>
> public int getId() {
> return id;
> }
>
> public void setId(int id) {
> this.id = id;
> }
>
> public String getName() {
> return name;
> }
>
> public void setName(String name) {
> this.name = name;
> }
>
> }
>
>
> public class PersonMOCacheStore implements CacheStore<Integer, PersonMO>{
>
> @SpringResource(resourceName = "pgDataSource")
> private DriverManagerDataSource pgDataSource;
>
> @LoggerResource
> private IgniteLogger log;
>
> //public void loadCache(IgniteBiInClosure<Integer, PersonMO> clo,
> @Nullable
> Object... args)
> @Override
> public void loadCache(IgniteBiInClosure<Integer, PersonMO> clo,
> Object...
> args)
> throws CacheLoaderException {
> log.info(">> Loading cache from store...");
>
> try(Connection conn = pgDataSource.getConnection()){
> try(PreparedStatement st =
> conn.prepareStatement("select * from
> PERSON")){
> try(ResultSet rs = st.executeQuery()){
> while(rs.next()) {
> PersonMO person = new
> PersonMO(rs.getInt(1),rs.getString(2),
> rs.getString(3));
>
> person.setCars(getCarSet(conn, person.getId() ) );
> clo.apply(person.getId(),
> person);
> }
> log.info(">> Finished Loading
> cache from store...");
> }
> }
> }catch(SQLException e) {
> throw new CacheLoaderException("Failed to load
> values from cache
> store.",e);
> }
>
> }
>
> //implementation for IgniteCache.get
> @Override
> public PersonMO load(Integer key) throws CacheLoaderException {
> log.info(">> Loading person from store...");
>
> try (Connection conn = pgDataSource.getConnection()) {
> try(PreparedStatement st =
> conn.prepareStatement("select * from PERSON
> where id = ?")){
> st.setString(1, key.toString());
> ResultSet rs = st.executeQuery();
> if(rs.next()) {
> PersonMO p= new
> PersonMO(rs.getInt(1),rs.getString(2),
> rs.getString(3));
> //p.setCars( getCarSet(conn,
> p.getId() ) );
> return p;
> }else {
> return null;
> }
>
>
> }
> }catch(SQLException e) {
> throw new CacheLoaderException("Failed to load
> values from cache
> store.",e);
> }
> }
>
>
> private Set<Car> getCarSet(Connection conn, int personId) throws
> SQLException{
> Set<Car> carSet = new HashSet<Car>();
> PreparedStatement st = conn.prepareStatement("select *
> from CAR where id =
> "+ personId);
> ResultSet rs = st.executeQuery();
>
> while(rs.next()) {
> carSet.add(new Car(rs.getInt(1),rs.getString(2) ));
> }
> return carSet;
> }
>
> }
>
>
>
>
> --
> Sent from: http://apache-ignite-users.70518.x6.nabble.com/
>
