https://github.com/guyschvitz/pgtools

Helper functions to interact with Postgres from R
https://github.com/guyschvitz/pgtools

Last synced: 9 days ago
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Helper functions to interact with Postgres from R

• Host: GitHub
• URL: https://github.com/guyschvitz/pgtools
• Owner: guyschvitz
• Created: 2020-10-27T10:52:40.000Z (about 4 years ago)
• Default Branch: master
• Last Pushed: 2021-03-26T09:27:02.000Z (over 3 years ago)
• Last Synced: 2024-08-13T07:13:35.864Z (4 months ago)
• Language: R
• Size: 21.5 KB
• Stars: 3
• Watchers: 1
• Forks: 1
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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• jimsghstars - guyschvitz/pgtools - Helper functions to interact with Postgres from R (R)

README

        
# pgtools

This package contains two functions that make it easier to fetch and store data from/to a Postgres database in R. 

## Installation

You can download and install the package from GitHub

```r

library(devtools)

install_github(repo = "guyschvitz/pgtools")

```

## pgViewTables: Search Tables in Database

This function offers an easy way look up all tables in the database by matching them to a search term (using PostgreSQL pattern matching). You can search either by schema name, table name or both. Leaving both the "table" and "schema" fields empty returns a dataframe of all tables in the database.

```r

library(pgtools)

library(RPostgres)

## Connect to DB

con <- dbConnect(Postgres(), host = MYHOST, user = MYUSER, 

                 dbname = MYDB, password = MYPASSWORD)

## Show all tables in schema maching "ras"

pgtools::pgViewTables(con, schema = "ras")

# table_schema   table_name

# 1  raster_tables hydepopc1880

# 2  raster_tables hydepopc1890

# 3  raster_tables hydepopc1900

# 4  raster_tables hydepopc1910

# 5  raster_tables hydepopc1920

# 6  raster_tables hydepopc1930

# 7  raster_tables hydepopc1940

# 8  raster_tables hydepopc1950

# 9  raster_tables hydepopc1960

# 10 raster_tables hydepopc1970

# 11 raster_tables hydepopc1980

# 12 raster_tables hydepopc1990

# 13 raster_tables hydepopc2000

# 14 raster_tables hydepopc2010

## Show all tables in schema matching "ras" with table names matching "19"

pgViewTables(con, schema = "ras", table = "19")

# table_schema   table_name

# 1  raster_tables hydepopc1900

# 2  raster_tables hydepopc1910

# 3  raster_tables hydepopc1920

# 4  raster_tables hydepopc1930

# 5  raster_tables hydepopc1940

# 6  raster_tables hydepopc1950

# 7  raster_tables hydepopc1960

# 8  raster_tables hydepopc1970

# 9  raster_tables hydepopc1980

# 10 raster_tables hydepopc1990

```

## pgRemoveLocks: Remove locks on tables in database

A common problem when trying to overwrite an existing PostgreSQL table is that the query hangs and never returns a result, which can cause your R session to crash entirely. This function finds and removes any locks in place on a given table so you can safely overwrite it.

```r

## Remove locks on all tables that match 'mytable'

pgRemoveLocks(con, 'mytable')

# [1] "No locks found"

## Overwrite 'mytable' with my.df

DBI::dbWriteTable(con, name = Id(schema = "myschema", table = "mytable"), my.df, overwrite=T)

```