Berkeley DB Reference Guide: Tuple - Using sorted collections
Description: Berkeley DB: An embedded database programmatic toolkit.
Keywords: embedded,database,programmatic,toolkit,b+tree,btree,hash,hashing,transaction,transactions,locking,logging,access method,access methods,Java,C,C++

### Berkeley DB Reference Guide: Java API Tutorial - Tuple |

### Tuple - Using sorted collections

In general, no changes to the prior example are necessary to use collections having tuple keys. Iteration of elements in a stored collection will be ordered by the sort order of the tuples. In addition to using the tuple format, the Db.DB_BTREE access method must be used when creating the database. Db.DB_BTREE is used for the databases in all examples. The Db.DB_HASH access method does not support sorted keys.

Although not shown in the example, all methods of the SortedMap and SortedSet interfaces may be used with sorted collections. For example, submaps and subsets may be created.

To create a sorted collection, the StoredSortedMap class is used instead of StoredMap .

>     import com.sleepycat.bdb.collection.StoredSortedMap;
>     ...
>     public class SampleViews
>     {
>         private StoredSortedMap partMap;
>         private StoredSortedMap supplierMap;
>         private StoredSortedMap shipmentMap;
>         private StoredSortedMap shipmentByPartMap;
>         private StoredSortedMap shipmentBySupplierMap;
>         private StoredSortedMap supplierByCityMap;
>         ...
>         public SampleViews(SampleDatabase db)
>         {
>             ...
>             partMap =
>                 new StoredSortedMap(db.getPartStore(),
>                               partKeyBinding, partValueBinding, true);
>             supplierMap =
>                 new StoredSortedMap(db.getSupplierStore(),
>                               supplierKeyBinding, supplierValueBinding, true);
>             shipmentMap =
>                 new StoredSortedMap(db.getShipmentStore(),
>                               shipmentKeyBinding, shipmentValueBinding, true);
>             shipmentByPartMap =
>                 new StoredSortedMap(db.getShipmentByPartIndex(),
>                               partKeyBinding, shipmentValueBinding, true);
>             shipmentBySupplierMap =
>                 new StoredSortedMap(db.getShipmentBySupplierIndex(),
>                               supplierKeyBinding, shipmentValueBinding, true);
>             supplierByCityMap =
>                 new StoredSortedMap(db.getSupplierByCityIndex(),
>                               cityKeyBinding, supplierValueBinding, true);
>         }
>     }

The getter methods of SampleViews also return StoredSortedMap and, as a convenience, StoredSortedValueSet .

>     import com.sleepycat.bdb.collection.StoredSortedMap;
>     import com.sleepycat.bdb.collection.StoredSortedValueSet;
>     ...
>     public class SampleViews
>     {
>         ...
>         public StoredSortedMap getPartMap()
>         {
>             return partMap;
>         }

>         public StoredSortedMap getSupplierMap()
>         {
>             return supplierMap;
>         }

>         public StoredSortedMap getShipmentMap()
>         {
>             return shipmentMap;
>         }

>         public StoredSortedValueSet getPartSet()
>         {
>             return (StoredSortedValueSet) partMap.values();
>         }

>         public StoredSortedValueSet getSupplierSet()
>         {
>             return (StoredSortedValueSet) supplierMap.values();
>         }

>         public StoredSortedValueSet getShipmentSet()
>         {
>             return (StoredSortedValueSet) shipmentMap.values();
>         }

>         public StoredSortedMap getShipmentByPartMap()
>         {
>             return shipmentByPartMap;
>         }

>         public StoredSortedMap getShipmentBySupplierMap()
>         {
>             return shipmentBySupplierMap;
>         }

>         public final StoredSortedMap getSupplierByCityMap()
>         {
>             return supplierByCityMap;
>         }
>         ...
>     }

The output of the example program shows that records are sorted by key value.

>     Adding Suppliers
>     Adding Parts
>     Adding Shipments

>     --- Parts ---
>     Part: number=P1 name=Nut color=Red weight=[12.0 grams] city=London
>     Part: number=P2 name=Bolt color=Green weight=[17.0 grams] city=Paris
>     Part: number=P3 name=Screw color=Blue weight=[17.0 grams] city=Rome
>     Part: number=P4 name=Screw color=Red weight=[14.0 grams] city=London
>     Part: number=P5 name=Cam color=Blue weight=[12.0 grams] city=Paris
>     Part: number=P6 name=Cog color=Red weight=[19.0 grams] city=London

>     --- Suppliers ---
>     Supplier: number=S1 name=Smith status=20 city=London
>     Supplier: number=S2 name=Jones status=10 city=Paris
>     Supplier: number=S3 name=Blake status=30 city=Paris
>     Supplier: number=S4 name=Clark status=20 city=London
>     Supplier: number=S5 name=Adams status=30 city=Athens

>     --- Suppliers for City Paris ---
>     Supplier: number=S2 name=Jones status=10 city=Paris
>     Supplier: number=S3 name=Blake status=30 city=Paris

>     --- Shipments ---
>     Shipment: part=P1 supplier=S1 quantity=300
>     Shipment: part=P1 supplier=S2 quantity=300
>     Shipment: part=P2 supplier=S1 quantity=200
>     Shipment: part=P2 supplier=S2 quantity=400
>     Shipment: part=P2 supplier=S3 quantity=200
>     Shipment: part=P2 supplier=S4 quantity=200
>     Shipment: part=P3 supplier=S1 quantity=400
>     Shipment: part=P4 supplier=S1 quantity=200
>     Shipment: part=P4 supplier=S4 quantity=300
>     Shipment: part=P5 supplier=S1 quantity=100
>     Shipment: part=P5 supplier=S4 quantity=400
>     Shipment: part=P6 supplier=S1 quantity=100

>     --- Shipments for Part P1 ---
>     Shipment: part=P1 supplier=S1 quantity=300
>     Shipment: part=P1 supplier=S2 quantity=300

>     --- Shipments for Supplier S1 ---
>     Shipment: part=P1 supplier=S1 quantity=300
>     Shipment: part=P2 supplier=S1 quantity=200
>     Shipment: part=P3 supplier=S1 quantity=400
>     Shipment: part=P4 supplier=S1 quantity=200
>     Shipment: part=P5 supplier=S1 quantity=100
>     Shipment: part=P6 supplier=S1 quantity=100

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