Query data from a Bigtable instance by creating a temporary table.
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For detailed documentation that includes this code sample, see the following:
Code sample
Java
Before trying this sample, follow the Java setup instructions in the BigQuery quickstart using client libraries . For more information, see the BigQuery Java API reference documentation .
To authenticate to BigQuery, set up Application Default Credentials. For more information, see Set up authentication for client libraries .
import
com.google.api.client.util. Base64
;
import
com.google.cloud.bigquery. BigQuery
;
import
com.google.cloud.bigquery. BigQueryException
;
import
com.google.cloud.bigquery. BigQueryOptions
;
import
com.google.cloud.bigquery. BigtableColumn
;
import
com.google.cloud.bigquery. BigtableColumnFamily
;
import
com.google.cloud.bigquery. BigtableOptions
;
import
com.google.cloud.bigquery. ExternalTableDefinition
;
import
com.google.cloud.bigquery. QueryJobConfiguration
;
import
com.google.cloud.bigquery. TableResult
;
import
com.google.common.collect.ImmutableList
;
// Sample to queries an external bigtable data source using a temporary table
public
class
QueryExternalBigtableTemp
{
public
static
void
main
(
String
[]
args
)
{
// TODO(developer): Replace these variables before running the sample.
String
projectId
=
"MY_PROJECT_ID"
;
String
bigtableInstanceId
=
"MY_INSTANCE_ID"
;
String
bigtableTableName
=
"MY_BIGTABLE_NAME"
;
String
bigqueryTableName
=
"MY_TABLE_NAME"
;
String
sourceUri
=
String
.
format
(
"https://googleapis.com/bigtable/projects/%s/instances/%s/tables/%s"
,
projectId
,
bigtableInstanceId
,
bigtableTableName
);
String
query
=
String
.
format
(
"SELECT * FROM %s "
,
bigqueryTableName
);
queryExternalBigtableTemp
(
bigqueryTableName
,
sourceUri
,
query
);
}
public
static
void
queryExternalBigtableTemp
(
String
tableName
,
String
sourceUri
,
String
query
)
{
try
{
// Initialize client that will be used to send requests. This client only needs to be created
// once, and can be reused for multiple requests.
BigQuery
bigquery
=
BigQueryOptions
.
getDefaultInstance
().
getService
();
BigtableColumnFamily
.
Builder
statsSummary
=
BigtableColumnFamily
.
newBuilder
();
// Configuring Columns
BigtableColumn
connectedCell
=
BigtableColumn
.
newBuilder
()
.
setQualifierEncoded
(
Base64
.
encodeBase64String
(
"connected_cell"
.
getBytes
()))
.
setFieldName
(
"connected_cell"
)
.
setType
(
"STRING"
)
.
setEncoding
(
"TEXT"
)
.
build
();
BigtableColumn
connectedWifi
=
BigtableColumn
.
newBuilder
()
.
setQualifierEncoded
(
Base64
.
encodeBase64String
(
"connected_wifi"
.
getBytes
()))
.
setFieldName
(
"connected_wifi"
)
.
setType
(
"STRING"
)
.
setEncoding
(
"TEXT"
)
.
build
();
BigtableColumn
osBuild
=
BigtableColumn
.
newBuilder
()
.
setQualifierEncoded
(
Base64
.
encodeBase64String
(
"os_build"
.
getBytes
()))
.
setFieldName
(
"os_build"
)
.
setType
(
"STRING"
)
.
setEncoding
(
"TEXT"
)
.
build
();
// Configuring column family and columns
statsSummary
.
setColumns
(
ImmutableList
.
of
(
connectedCell
,
connectedWifi
,
osBuild
))
.
setFamilyID
(
"stats_summary"
)
.
setOnlyReadLatest
(
true
)
.
setEncoding
(
"TEXT"
)
.
setType
(
"STRING"
)
.
build
();
// Configuring BigtableOptions is optional.
BigtableOptions
options
=
BigtableOptions
.
newBuilder
()
.
setIgnoreUnspecifiedColumnFamilies
(
true
)
.
setReadRowkeyAsString
(
true
)
.
setColumnFamilies
(
ImmutableList
.
of
(
statsSummary
.
build
()))
.
build
();
// Configure the external data source and query job.
ExternalTableDefinition
externalTable
=
ExternalTableDefinition
.
newBuilder
(
sourceUri
,
options
).
build
();
QueryJobConfiguration
queryConfig
=
QueryJobConfiguration
.
newBuilder
(
query
)
.
addTableDefinition
(
tableName
,
externalTable
)
.
build
();
// Example query
TableResult
results
=
bigquery
.
query
(
queryConfig
);
results
.
iterateAll
()
.
forEach
(
row
-
>
row
.
forEach
(
val
-
>
System
.
out
.
printf
(
"%s,"
,
val
.
toString
())));
System
.
out
.
println
(
"Query on external temporary table performed successfully."
);
}
catch
(
BigQueryException
|
InterruptedException
e
)
{
System
.
out
.
println
(
"Query not performed \n"
+
e
.
toString
());
}
}
}
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