Creating a Sequence

You create a sequence by using the TableOperationFactory class to create TableOperation class instances, each of which represents exactly one operation in the store. You obtain an instance of TableOperationFactory by using TableAPI.getTableOperationFactory().

For example, suppose you are using a table defined like this:

CREATE TABLE myTable (
    itemType STRING,
    itemCategory STRING,
    itemClass STRING,
    itemColor STRING,
    itemSize STRING,
    price FLOAT,
    inventoryCount INTEGER,
    PRIMARY KEY (SHARD(itemType, itemCategory, itemClass), itemColor,
    itemSize)
) 

With tables containing data like this:

• Row 1:

  • itemType: Hats

  • itemCategory: baseball

  • itemClass: longbill

  • itemColor: red

  • itemSize: small

  • price: 12.07

  • inventoryCount: 127

• Row 2:

  • itemType: Hats

  • itemCategory: baseball

  • itemClass: longbill

  • itemColor: red

  • itemSize: medium

  • price: 13.07

  • inventoryCount: 201

• Row 3:

  • itemType: Hats

  • itemCategory: baseball

  • itemClass: longbill

  • itemColor: red

  • itemSize: large

  • price: 14.07

  • inventoryCount: 39

And further suppose that this table has rows that require an update (such as a price and inventory refresh), and you want the update to occur in such a fashion as to ensure it is performed consistently for all the rows.

Then you can create a sequence in the following way:

package kvstore.basicExample;

import java.util.ArrayList;

import oracle.kv.KVStore;
import oracle.kv.KVStoreConfig;
import oracle.kv.KVStoreFactory;

import oracle.kv.DurabilityException;
import oracle.kv.FaultException;
import oracle.kv.OperationExecutionException;
import oracle.kv.RequestTimeoutException;

import oracle.kv.table.PrimaryKey;
import oracle.kv.table.Row;
import oracle.kv.table.Table;
import oracle.kv.table.TableAPI;
import oracle.kv.table.TableOperationFactory;
import oracle.kv.table.TableOperation;

...

// kvstore handle creation omitted.

...

TableAPI tableH = kvstore.getTableAPI();

Table myTable = tableH.getTable("myTable");

// We use TableOperationFactory to create items for our
// sequence.
TableOperationFactory tof = tableH.getTableOperationFactory();

// This ArrayList is used to contain each item in our sequence.
ArrayList<TableOperation> opList = new ArrayList<TableOperation>();

// Update each row, adding each to the opList as we do.
Row row = myTable.createRow();
row.put("itemType", "Hats");
row.put("itemCategory", "baseball");
row.put("itemClass", "longbill");
row.put("itemColor", "red");
row.put("itemSize", "small");
row.put("price", new Float(13.07));
row.put("inventoryCount", 107);
opList.add(tof.createPut(row, null, true));

row = myTable.createRow();
row.put("itemType", "Hats");
row.put("itemCategory", "baseball");
row.put("itemClass", "longbill");
row.put("itemColor", "red");
row.put("itemSize", "medium");
row.put("price", new Float(14.07));
row.put("inventoryCount", 198);
opList.add(tof.createPut(row, null, true));

row = myTable.createRow();
row.put("itemType", "Hats");
row.put("itemCategory", "baseball");
row.put("itemClass", "longbill");
row.put("itemColor", "red");
row.put("itemSize", "large");
row.put("price", new Float(15.07));
row.put("inventoryCount", 139);
opList.add(tof.createPut(row, null, true)); 

Note in the above example that we update only those rows that share the same shard key. In this case, the shard key includes the itemType, itemCategory, and itemClass fields. If the value for any of those fields is different from the others, we could not successfully execute the sequence.