```
public interface Connection
```
A Connection is a session between a Java application and BigQuery. SQL statements are executed and results are returned within the context of a connection.

Method Summary

All Methods Instance Methods Abstract Methods
Modifier and Type	Method	Description
`boolean`	`close()`	Sends a query cancel request.
`BigQueryDryRunResult`	`dryRun(String sql)`	Execute a query dry run that returns information on the schema and query parameters of the query results.
`BigQueryResult`	`executeSelect(String sql)`	Execute a SQL statement that returns a single ResultSet.
`BigQueryResult`	`executeSelect(String sql, List<Parameter> parameters, Map<String,String>... labels)`	This method executes a SQL SELECT query
`com.google.common.util.concurrent.ListenableFuture<ExecuteSelectResponse>`	`executeSelectAsync(String sql)`	Execute a SQL statement that returns a single ResultSet and returns a ListenableFuture to process the response asynchronously.
`com.google.common.util.concurrent.ListenableFuture<ExecuteSelectResponse>`	`executeSelectAsync(String sql, List<Parameter> parameters, Map<String,String>... labels)`	Execute a SQL statement that returns a single ResultSet and returns a ListenableFuture to process the response asynchronously.

Method Detail

close
```
@BetaApi
boolean close()
       throws BigQuerySQLException
```
Sends a query cancel request. This call will return immediately

Throws:

BigQuerySQLException

dryRun
```
@BetaApi
BigQueryDryRunResult dryRun(String sql)
                     throws BigQuerySQLException
```
Execute a query dry run that returns information on the schema and query parameters of the query results.

Parameters:

sql - typically a static SQL SELECT statement

Throws:

BigQuerySQLException - if a database access error occurs

executeSelect

@BetaApi
BigQueryResult executeSelect(String sql)
                      throws BigQuerySQLException

Execute a SQL statement that returns a single ResultSet.

Example of running a query.

 {
   @code
   ConnectionSettings connectionSettings =
        ConnectionSettings.newBuilder()
            .setRequestTimeout(10L)
            .setMaxResults(100L)
            .setUseQueryCache(true)
            .build();
   Connection connection = bigquery.createConnection(connectionSettings);
   String selectQuery = "SELECT corpus FROM `bigquery-public-data.samples.shakespeare` GROUP BY corpus;";
   BigQueryResult bqResultSet = connection.executeSelect(selectQuery)
   ResultSet rs = bqResultSet.getResultSet();
   while (rs.next()) {
       System.out.printf("%s,", rs.getString("corpus"));
   }

Parameters:: sql - a static SQL SELECT statement
Returns:: a ResultSet that contains the data produced by the query
Throws:: BigQuerySQLException - if a database access error occurs

executeSelect
```
@BetaApi
BigQueryResult executeSelect(String sql,
                             List<Parameter> parameters,
                             Map<String,String>... labels)
                      throws BigQuerySQLException
```
This method executes a SQL SELECT query

Parameters:

sql - SQL SELECT query

parameters - named or positional parameters. The set of query parameters must either be all positional or all named parameters.

labels - (optional) the labels associated with this query. You can use these to organize and group your query jobs. Label keys and values can be no longer than 63 characters, can only contain lowercase letters, numeric characters, underscores and dashes. International characters are allowed. Label values are optional and Label is a Varargs. You should pass all the Labels in a single Map .Label keys must start with a letter and each label in the list must have a different key.

Returns:

BigQueryResult containing the output of the query

Throws:

BigQuerySQLException

executeSelectAsync

@BetaApi
com.google.common.util.concurrent.ListenableFuture<ExecuteSelectResponse> executeSelectAsync(String sql)
                                                                                      throws BigQuerySQLException

Execute a SQL statement that returns a single ResultSet and returns a ListenableFuture to process the response asynchronously.

Example of running a query.

 {
   @code
  ConnectionSettings connectionSettings =
        ConnectionSettings.newBuilder()
            .setUseReadAPI(true)
            .build();
   Connection connection = bigquery.createConnection(connectionSettings);
   String selectQuery = "SELECT corpus FROM `bigquery-public-data.samples.shakespeare` GROUP BY corpus;";
 ListenableFuture<ExecuteSelectResponse> executeSelectFuture = connection.executeSelectAsync(selectQuery);
 ExecuteSelectResponse executeSelectRes = executeSelectFuture.get();

  if(!executeSelectRes.getIsSuccessful()){
 throw executeSelectRes.getBigQuerySQLException();
 }

  BigQueryResult bigQueryResult = executeSelectRes.getBigQueryResult();
 ResultSet rs = bigQueryResult.getResultSet();
 while (rs.next()) {
 System.out.println(rs.getString(1));
 }

Parameters:: sql - a static SQL SELECT statement
Returns:: a ListenableFuture that is used to get the data produced by the query
Throws:: BigQuerySQLException - upon failure

executeSelectAsync

@BetaApi
com.google.common.util.concurrent.ListenableFuture<ExecuteSelectResponse> executeSelectAsync(String sql,
                                                                                             List<Parameter> parameters,
                                                                                             Map<String,String>... labels)
                                                                                      throws BigQuerySQLException

Execute a SQL statement that returns a single ResultSet and returns a ListenableFuture to process the response asynchronously.

Example of running a query.

 {
   @code
  ConnectionSettings connectionSettings =
        ConnectionSettings.newBuilder()
            ..setUseReadAPI(true)
            .build();
   Connection connection = bigquery.createConnection(connectionSettings);
     String selectQuery =
         "SELECT TimestampField, StringField, BooleanField FROM "
             + MY_TABLE
             + " WHERE StringField = @stringParam"
             + " AND IntegerField IN UNNEST(@integerList)";
     QueryParameterValue stringParameter = QueryParameterValue.string("stringValue");
     QueryParameterValue intArrayParameter =
         QueryParameterValue.array(new Integer[] {3, 4}, Integer.class);
     Parameter stringParam =
         Parameter.newBuilder().setName("stringParam").setValue(stringParameter).build();
     Parameter intArrayParam =
         Parameter.newBuilder().setName("integerList").setValue(intArrayParameter).build();
     List<Parameter> parameters = ImmutableList.of(stringParam, intArrayParam);

     ListenableFuture<ExecuteSelectResponse> executeSelectFut =
         connection.executeSelectAsync(selectQuery, parameters);
 ExecuteSelectResponse executeSelectRes = executeSelectFuture.get();

  if(!executeSelectRes.getIsSuccessful()){
 throw executeSelectRes.getBigQuerySQLException();
 }

  BigQueryResult bigQueryResult = executeSelectRes.getBigQueryResult();
 ResultSet rs = bigQueryResult.getResultSet();
 while (rs.next()) {
 System.out.println(rs.getString(1));
 }

Parameters:: sql - SQL SELECT query; parameters - named or positional parameters. The set of query parameters must either be all positional or all named parameters.; labels - (optional) the labels associated with this query. You can use these to organize and group your query jobs. Label keys and values can be no longer than 63 characters, can only contain lowercase letters, numeric characters, underscores and dashes. International characters are allowed. Label values are optional and Label is a Varargs. You should pass all the Labels in a single Map .Label keys must start with a letter and each label in the list must have a different key.
Returns:: a ListenableFuture that is used to get the data produced by the query
Throws:: BigQuerySQLException - upon failure

Interface Connection

Method Summary

Method Detail

close

dryRun

executeSelect

executeSelect

executeSelectAsync

executeSelectAsync