Using multiGet()

TableAPI.multiGet() allows you to retrieve multiple rows at once, so long as they all share the same shard keys. You can specify a full set of shard keys, or a partial set.

Use TableAPI.multiGet() only if your retrieval set will fit entirely in memory.

For example, suppose you have a table that stores information about products, which is designed like this:

## Enter into table creation mode
table create -name myTable
## Now add the fields
add-field -type STRING -name itemType
add-field -type STRING -name itemCategory
add-field -type STRING -name itemClass
add-field -type STRING -name itemColor
add-field -type STRING -name itemSize
add-field -type FLOAT -name price
add-field -type INTEGER -name inventoryCount
primary-key -field itemType -field itemCategory -field itemClass
-field itemColor -field itemSize
shard-key -field itemType -field itemCategory -field itemClass
## Exit table creation mode

With tables containing data like this:

In this case, you can retrieve all of the rows with their itemType field set to Hats and their itemCategory field set to baseball. Notice that this represents a partial primary key, because itemClass, itemColor and itemSize are not used for this query.

package kvstore.basicExample;


import java.util.List;
import java.util.Iterator;
import oracle.kv.ConsistencyException;
import oracle.kv.KVStore;
import oracle.kv.RequestTimeoutException;
import oracle.kv.table.PrimaryKey;
import oracle.kv.table.Row;
import oracle.kv.table.Table;
import oracle.kv.table.TableAPI;


// KVStore handle creation is omitted for brevity


TableAPI tableH = kvstore.getTableAPI();

// The name you give to getTable() must be identical
// to the name that you gave the table when you created
// the table using the CLI's 'table create' command.
Table myTable = tableH.getTable("myTable");

// Construct the PrimaryKey. In this case, we are
// using a partial primary key.
PrimaryKey key = myTable.createPrimaryKey();
key.put("itemType", "Hats");
key.put("itemCategory", "baseball");

List<Row> myRows = null;

try {
    myRows = tableH.multiGet(key, null, null);
} catch (ConsistencyException ce) {
    // The consistency guarantee was not met
} catch (RequestTimeoutException re) {
    // The operation was not completed within the
    // timeout value

You can then iterate over the resulting list as follows:

for (Rows theRow: myRows) {
    String itemType = theRow.get("itemType").asString.get();
    String itemCategory = theRow.get("itemCategory").asString.get();
    String itemClass = theRow.get("itemClass").asString.get();
    String itemColor = theRow.get("itemColor").asString.get();
    String itemSize = theRow.get("itemSize").asString.get();
    Float price = theRow.get("price").asFloat.get();
    Integer price = theRow.get("itemCount").asInteger.get();