Practice Test 4 | Google Cloud Certified Professional Data Engineer | Dumps | Mock Test
Your company has configured a streaming data pipeline, data from thousands of Internet of Things devices is processed using Pub-Sub and dataflow and then is ingested in BigQuery in real-time. The data in big query is stored into an ingestion-time partitioned table. You want to run SQL queries against your data for analysis. How would you run SQL queries against a particular partition?
A. Use the DATE column in the WHERE clause to filter results for a particular date.
B. Use the _PARTITIONTIME pseudo-column in the WHERE clause
C. Use the column DAY_TIMESTAMP created during ingestion, filter the content of the table by applying the WHERE clause on this column
D. Use the _PARTITION_TIME pseudo-column in the WHERE clause
The correct answer is B
Option A is incorrect. As the table is an ingestion-time partitioned table, pseudo-column _PARTITTIONTIME is c+reated. No DATE column exists in the big query table for this data set.
Option B is correct. Ingestion-time partitioned table contains a pseudo column _PARTITTIONTIME. Refer below explanation
When you create an ingestion-time partitioned table, two pseudo columns are added to the table: a
_PARTITIONTIME pseudo column and a _PARTITIONDATE pseudo column. The _PARTITIONTIME pseudo column contains a date-based timestamp for data that is loaded into the table. The _PARTITIONDATE pseudo column contains a date representation. Both pseudo column names are reserved, which means that you cannot create a column with either name in any of your tables.
_PARTITIONTIME and _PARTITIONDATE are available only in ingestion-time partitioned tables. Partitioned tables do not have pseudo columns. The _PARTITIONTIME pseudo column
The _PARTITIONTIME pseudo column contains a timestamp that is based on UTC time and represents the number of microseconds since the Unix epoch. For example, if data is appended to a table on April 15, 2016, all of the rows of data that are appended on that day contain the value TIMESTAMP(“2016-04- 15”) in the _PARTITIONTIME column.
Option C is incorrect. As the table created, is an Ingestion-time partitioned table only two pseudo columns are created _PARTITIONTIME and _PARTITIONDATE. DAY_TIMESTAMP columns that do not exist are not created by the ingestion time partitioned table.
Option D is incorrect. Ingestion-time partitioned table creates two pseudo columns _PARTITIONTIME and _PARTITIONDATE. The syntax of the pseudo column _PARTITION_TIME is not correct.
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