Bigquery Data Load with Command Line

Data Load with Command Line

Data load using bq involves three types:

1. Empty (Default): It writes data into an empty table, if data already exists it throws error.

bq query  ---n=1000 --destination_table=<table_name> 'SELECT * FROM [project:dataset.source_table];'

2. Replace: It replace a current table with newly obtained data output. 
It involves loss of existing data in a destination table. 
Use it wisely to perform incremental load which involves update and inserts.

bq query  ---replace --destination_table=<table_name> 'SELECT * FROM [project:dataset.source_table];'

3. Append: It appends new records to the existing table. 
If same command is executed more than one time it will create duplicate records. 
Can be used for incremental load which involves only data insert. 
bq query  ---append_table --destination_table=<table_name> 'SELECT * FROM [project:dataset.source_table];'

SQL 2016 New Features

Query Store: The Query Store feature maintains a history of query execution plans with their performance data, and quickly identifies queries that have gotten slower recently, allowing administrators or developers to force the use of an older, better plan if needed.

Polybase: This feature will benefit you if your regular data processing involves dealing with a lot of large text files -- they can be stored in Azure Blob Storage or Hadoop, and queried as if they were database tables. 

Stretch Database: The basics of Stretch Database are that some part of your tables (configurable or automated) will be moved into an Azure SQL Database in the cloud in a secure fashion. When you query those tables, the query optimizer knows which rows are on your server and which rows are in Azure, and divides the workload accordingly. 

JSON Support: Providing the ability to quickly move JSON data into tables

Row Level Security: This restricts which users can view what data in a table, based on a function. SQL Server 2016 introduces this feature, which is very useful in multi-tenant environments where you may want to limit data access based on customer ID.

Always Encrypted: Always Encrypted is new functionality through the use of an enhanced client library at the application so the data stays encrypted in transit, at rest and while it is alive in the database.

In-Memory Enhancements: Optimally designed for high-speed loading of data with no locking issues or high-volume session state issues.