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dbtools

About

A package that is used to run SQL queries configured for the Analytical Platform. This package is a reticulated wrapper around pydbtools which uses AWS Wrangler's Athena module but adds additional functionality (like Jinja templating, creating temporary tables) and alters some configuration to our specification.

Alternatively you probably want to use Rdbtools, which has the advantages of supporting dbplyr and being R-native, so there's no messing with reticulate and Python which cause endless problems.

Installation

Run the following commands in the R console.

# Set up the project to use renv, if not already done
renv::init()
# Tell renv that Python will be used
renv::use_python()
# Install the reticulate library to interface with Python
renv::install("reticulate")
# Install the Python library pydbtools
reticulate::py_install("pydbtools")
# Install dbtools
renv::install("moj-analytical-services/dbtools")

Quickstart guide

There is a vignette with more details but the following describes the basics of the package.

Read an SQL Athena query into an R dataframe

library(dbtools)

df <- read_sql_query("SELECT * from a_database.table LIMIT 10")

Run a query in Athena

response <- dbtools::start_query_execution_and_wait(
  "CREATE DATABASE IF NOT EXISTS my_test_database"
)

Create temporary tables to do further separate SQL queries on later

dbtools::create_temp_table(
  "SELECT a_col, count(*) as n FROM a_database.table GROUP BY a_col", 
  table_name="temp_table_1"
)
df <- dbtools::read_sql_query("SELECT * FROM __temp__.temp_table_1 WHERE n < 10")

Delete databases, tables and partitions together with the data on S3

dbtools::delete_partitions_and_data(
  database='my_database', 
  table='my_table', 
  expression='year = 2020 or year = 2021'
)
dbtools::delete_table_and_data(database='my_database', table='my_table')
dbtools::delete_database('my_database')

# These can be used for temporary databases and tables.
dbtools::delete_table_and_data(database='__temp__', table='my_temp_table')

Use Jinja templating to inject arguments into your SQL

sql_template <- "SELECT * FROM {{ db_name }}.{{ table }}"
sql <- dbtools::render_sql_template(sql_template, {"db_name": db_name, "table": "department"})
df <- dbtools::read_sql_query(sql)

cat("SELECT * FROM {{ db_name }}.{{ table_name }}", file="tempfile.sql")
sql <- dbtools::get_sql_from_file("tempfile.sql", jinja_args={"db_name": db_name, "table_name": "department"})
dbtools::read_sql_query(sql)

Changelog:

3.0.0 - 2022-02-03

  • No longer dependent on s3tools
  • Wraps pydbtools functions

2.0.3 - 2020-04-29

  • Fixes prompts to install miniconda - now automatically uses main Analytical Platform Conda Python, based on sys path

2.0.2 - 2019-06-14

  • Fixed issue where credentials would not refresh
  • Is now dependant on pydbtools package
  • SQL queries like SHOW COLUMNS FROM db.table now work for read_sql and return a df.

2.0.1 - 2019-04-23

  • Updated the version in the DESCRIPTION file to the correct version

v2.0.0 - 2019-02-08

  • Removed input parameters bucket and output_folder from read_sql and get_athena_query_response functions. New section to README named 'Under The Hood' explains why.
  • Note package now requires the group policy StandardDatabaseAccess to be attached to the role that needs to use this package.

v1.0.0 - 2019-01-14

  • Added function read_sql which reads an SQL query directly into an R dataframe. See R documentation (i.e. ?read_sql)
  • Input parameter out_path in function get_athena_query_response has been replaced by two input parameters bucket and output_folder. E.g. If your out_path="s3://my-bucket/__temp__" then the new input params are bucket=my-bucket and output_folder=__temp__. Note that output_folder defaults to value __athena_temp__ it is recommended that you leave this unchanged.

v0.0.2 - 2018-10-12

  • timeout is now an input parameter to get_athena_query_response if not set there is no timeout for the athena query.
  • get_athena_query_response will now print out the athena_client response if the athena query fails.

v0.0.1 - First Release