Add an empty column

  import 
  
 ( 
  
 "context" 
  
 "fmt" 
  
 "cloud.google.com/go/bigquery" 
 ) 
 // updateTableAddColumn demonstrates modifying the schema of a table to append an additional column. 
 func 
  
 updateTableAddColumn 
 ( 
 projectID 
 , 
  
 datasetID 
 , 
  
 tableID 
  
 string 
 ) 
  
 error 
  
 { 
  
 // projectID := "my-project-id" 
  
 // datasetID := "mydataset" 
  
 // tableID := "mytable" 
  
 ctx 
  
 := 
  
 context 
 . 
 Background 
 () 
  
 client 
 , 
  
 err 
  
 := 
  
 bigquery 
 . 
 NewClient 
 ( 
 ctx 
 , 
  
 projectID 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 fmt 
 . 
 Errorf 
 ( 
 "bigquery.NewClient: %w" 
 , 
  
 err 
 ) 
  
 } 
  
 defer 
  
 client 
 . 
 Close 
 () 
  
 tableRef 
  
 := 
  
 client 
 . 
 Dataset 
 ( 
 datasetID 
 ). 
 Table 
 ( 
 tableID 
 ) 
  
 meta 
 , 
  
 err 
  
 := 
  
 tableRef 
 . 
 Metadata 
 ( 
 ctx 
 ) 
  
 if 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 err 
  
 } 
  
 newSchema 
  
 := 
  
 append 
 ( 
 meta 
 . 
  Schema 
 
 , 
  
& bigquery 
 . 
  FieldSchema 
 
 { 
 Name 
 : 
  
 "phone" 
 , 
  
 Type 
 : 
  
 bigquery 
 . 
  StringFieldType 
 
 }, 
  
 ) 
  
 update 
  
 := 
  
 bigquery 
 . 
  TableMetadataToUpdate 
 
 { 
  
 Schema 
 : 
  
 newSchema 
 , 
  
 } 
  
 if 
  
 _ 
 , 
  
 err 
  
 := 
  
 tableRef 
 . 
 Update 
 ( 
 ctx 
 , 
  
 update 
 , 
  
 meta 
 . 
 ETag 
 ); 
  
 err 
  
 != 
  
 nil 
  
 { 
  
 return 
  
 err 
  
 } 
  
 return 
  
 nil 
 } 
 

  import 
  
 com.google.cloud.bigquery. BigQuery 
 
 ; 
 import 
  
 com.google.cloud.bigquery. BigQueryException 
 
 ; 
 import 
  
 com.google.cloud.bigquery. BigQueryOptions 
 
 ; 
 import 
  
 com.google.cloud.bigquery. Field 
 
 ; 
 import 
  
 com.google.cloud.bigquery. FieldList 
 
 ; 
 import 
  
 com.google.cloud.bigquery. LegacySQLTypeName 
 
 ; 
 import 
  
 com.google.cloud.bigquery. Schema 
 
 ; 
 import 
  
 com.google.cloud.bigquery. StandardTableDefinition 
 
 ; 
 import 
  
 com.google.cloud.bigquery. Table 
 
 ; 
 import 
  
 java.util.ArrayList 
 ; 
 import 
  
 java.util.List 
 ; 
 public 
  
 class 
 AddEmptyColumn 
  
 { 
  
 public 
  
 static 
  
 void 
  
 main 
 ( 
 String 
 [] 
  
 args 
 ) 
  
 { 
  
 // TODO(developer): Replace these variables before running the sample. 
  
 String 
  
 datasetName 
  
 = 
  
 "MY_DATASET_NAME" 
 ; 
  
 String 
  
 tableId 
  
 = 
  
 "MY_TABLE_NAME" 
 ; 
  
 String 
  
 newColumnName 
  
 = 
  
 "NEW_COLUMN_NAME" 
 ; 
  
 addEmptyColumn 
 ( 
 newColumnName 
 , 
  
 datasetName 
 , 
  
 tableId 
 ); 
  
 } 
  
 public 
  
 static 
  
 void 
  
 addEmptyColumn 
 ( 
 String 
  
 newColumnName 
 , 
  
 String 
  
 datasetName 
 , 
  
 String 
  
 tableId 
 ) 
  
 { 
  
 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 
 (); 
  
  Table 
 
  
 table 
  
 = 
  
 bigquery 
 . 
  getTable 
 
 ( 
 datasetName 
 , 
  
 tableId 
 ); 
  
  Schema 
 
  
 schema 
  
 = 
  
 table 
 . 
  getDefinition 
 
 (). 
 getSchema 
 (); 
  
  FieldList 
 
  
 fields 
  
 = 
  
 schema 
 . 
  getFields 
 
 (); 
  
 // Create the new field/column 
  
  Field 
 
  
 newField 
  
 = 
  
  Field 
 
 . 
 of 
 ( 
 newColumnName 
 , 
  
  LegacySQLTypeName 
 
 . 
 STRING 
 ); 
  
 // Create a new schema adding the current fields, plus the new one 
  
 List<Field> 
  
 fieldList 
  
 = 
  
 new 
  
 ArrayList<Field> 
 (); 
  
 fields 
 . 
 forEach 
 ( 
 fieldList 
 :: 
 add 
 ); 
  
 fieldList 
 . 
 add 
 ( 
 newField 
 ); 
  
  Schema 
 
  
 newSchema 
  
 = 
  
  Schema 
 
 . 
 of 
 ( 
 fieldList 
 ); 
  
 // Update the table with the new schema 
  
  Table 
 
  
 updatedTable 
  
 = 
  
 table 
 . 
  toBuilder 
 
 (). 
 setDefinition 
 ( 
  StandardTableDefinition 
 
 . 
 of 
 ( 
 newSchema 
 )). 
 build 
 (); 
  
  update 
 
dTable . 
  update 
 
 (); 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "Empty column successfully added to table" 
 ); 
  
 } 
  
 catch 
  
 ( 
  BigQueryException 
 
  
 e 
 ) 
  
 { 
  
 System 
 . 
 out 
 . 
 println 
 ( 
 "Empty column was not added. \n" 
  
 + 
  
 e 
 . 
 toString 
 ()); 
  
 } 
  
 } 
 } 
 

  // Import the Google Cloud client library and create a client 
 const 
  
 { 
 BigQuery 
 } 
  
 = 
  
 require 
 ( 
 ' @google-cloud/bigquery 
' 
 ); 
 const 
  
 bigquery 
  
 = 
  
 new 
  
  BigQuery 
 
 (); 
 async 
  
 function 
  
 addEmptyColumn 
 () 
  
 { 
  
 // Adds an empty column to the schema. 
  
 /** 
 * TODO(developer): Uncomment the following lines before running the sample. 
 */ 
  
 // const datasetId = 'my_dataset'; 
  
 // const tableId = 'my_table'; 
  
 const 
  
 column 
  
 = 
  
 { 
 name 
 : 
  
 'size' 
 , 
  
 type 
 : 
  
 'STRING' 
 }; 
  
 // Retrieve current table metadata 
  
 const 
  
 table 
  
 = 
  
 bigquery 
 . 
 dataset 
 ( 
 datasetId 
 ). 
 table 
 ( 
 tableId 
 ); 
  
 const 
  
 [ 
 metadata 
 ] 
  
 = 
  
 await 
  
 table 
 . 
 getMetadata 
 (); 
  
 // Update table schema 
  
 const 
  
 schema 
  
 = 
  
 metadata 
 . 
 schema 
 ; 
  
 const 
  
 new_schema 
  
 = 
  
 schema 
 ; 
  
 new_schema 
 . 
 fields 
 . 
 push 
 ( 
 column 
 ); 
  
 metadata 
 . 
 schema 
  
 = 
  
 new_schema 
 ; 
  
 const 
  
 [ 
 result 
 ] 
  
 = 
  
 await 
  
 table 
 . 
 setMetadata 
 ( 
 metadata 
 ); 
  
 console 
 . 
 log 
 ( 
  result 
 
 . 
 schema 
 . 
 fields 
 ); 
 } 
 

  from 
  
 google.cloud 
  
 import 
  bigquery 
 
 # Construct a BigQuery client object. 
 client 
 = 
  bigquery 
 
 . 
  Client 
 
 () 
 # TODO(developer): Set table_id to the ID of the table 
 #                  to add an empty column. 
 # table_id = "your-project.your_dataset.your_table_name" 
 table 
 = 
 client 
 . 
  get_table 
 
 ( 
 table_id 
 ) 
 # Make an API request. 
 original_schema 
 = 
 table 
 . 
 schema 
 new_schema 
 = 
 original_schema 
 [:] 
 # Creates a copy of the schema. 
 new_schema 
 . 
 append 
 ( 
  bigquery 
 
 . 
  SchemaField 
 
 ( 
 "phone" 
 , 
 "STRING" 
 )) 
 table 
 . 
 schema 
 = 
 new_schema 
 table 
 = 
 client 
 . 
  update_table 
 
 ( 
 table 
 , 
 [ 
 "schema" 
 ]) 
 # Make an API request. 
 if 
 len 
 ( 
 table 
 . 
 schema 
 ) 
 == 
 len 
 ( 
 original_schema 
 ) 
 + 
 1 
 == 
 len 
 ( 
 new_schema 
 ): 
 print 
 ( 
 "A new column has been added." 
 ) 
 else 
 : 
 print 
 ( 
 "The column has not been added." 
 )