https://github.com/meerapatelmd/pg13
R Package for connecting to and querying a Postgres database
https://github.com/meerapatelmd/pg13
Last synced: 4 months ago
JSON representation
R Package for connecting to and querying a Postgres database
- Host: GitHub
- URL: https://github.com/meerapatelmd/pg13
- Owner: meerapatelmd
- Created: 2020-07-17T22:17:29.000Z (over 4 years ago)
- Default Branch: master
- Last Pushed: 2021-12-20T21:13:54.000Z (over 3 years ago)
- Last Synced: 2024-08-13T07:13:34.734Z (8 months ago)
- Language: R
- Homepage: https://meerapatelmd.github.io/pg13/
- Size: 6.24 MB
- Stars: 1
- Watchers: 1
- Forks: 2
- Open Issues: 6
-
Metadata Files:
- Readme: README.Rmd
- Changelog: NEWS.md
- Contributing: .github/CONTRIBUTING.md
- Code of conduct: .github/CODE_OF_CONDUCT.md
- Support: .github/SUPPORT.md
Awesome Lists containing this project
- jimsghstars - meerapatelmd/pg13 - R Package for connecting to and querying a Postgres database (R)
README
---
output: github_document
---
```{r, include = FALSE}
knitr::opts_chunk$set(
collapse = TRUE,
comment = "#>",
fig.path = "man/figures/README-",
out.width = "100%"
)
```
# pg13 
Functionalized rendering, reading, and building of PostgreSQL statements using R.
Other functions from the DatabaseConnector package are migrated here with added
conditional steps, such as warning the user that a resultset has 0 rows, verbosity
such that it is interactively known what operations are taking place, or SQL
rendering in the console before the statement is sent and/or queried for
troubleshooting in a separate client.
## Installation
Install the development version from [GitHub](https://github.com/) with:
``` r
# install.packages("devtools")
devtools::install_github("meerapatelmd/pg13")
```
## Example
pg13 provides functions that simplifies queries such as joins from the R console.
First, a connection is made to Postgres. Here, I am connecting to my test database `pg13_test`.
```{r,results='hide',message=FALSE}
library(pg13)
conn <- local_connect(dbname = "pg13_test")
```
```{r example_setup, include=FALSE}
create_test_schema <-
function(conn) {
if (!schema_exists(conn = conn,
schema = "test_schema")) {
create_schema(conn = conn,
schema = "test_schema")
}
}
create_test_schema(conn = conn)
# Write a table to join to without dropping
write_table(conn = conn,
schema = "test_schema",
table_name = "test_table2",
drop_existing = TRUE,
data = data.frame(A = 1:25, B = letters[1:25]))
```
I write a target table in the test database with sample data:
```{r}
test_table <- data.frame(A = 1:25, B = letters[1:25])
head(test_table)
```
The data is written to the target `schema` and `table_name` or "test_schema" and "test_table2" respectively. Messages appear in the console along with timestamp that elaborate on the connection status, the data dimensions, and the passage of QA checks.
```{r}
write_table(conn = conn,
schema = "test_schema",
table_name = "test_table2",
drop_existing = TRUE,
data = data.frame(A = 1:25, B = letters[1:25]))
```
I create another dataframe in the R environment to serve as left-side table for this demonstration.
```{r}
test_data <-
data.frame(A = 1:100, B = letters[1:100])
head(test_data)
```
I can then perform various joins between this dataframe and the previously written table, such as an inner join
```{r}
join1(conn = conn,
write_schema = "public",
data = test_data,
column = "A",
kind = "INNER",
join_on_schema = "test_schema",
join_on_table = "test_table2",
join_on_column = "A")
```
a right join
```{r}
join1(conn = conn,
write_schema = "public",
data = test_data,
column = "A",
kind = "RIGHT",
join_on_schema = "test_schema",
join_on_table = "test_table2",
join_on_column = "A")
```
a left join
```{r}
join1(conn = conn,
write_schema = "public",
data = test_data,
column = "A",
kind = "LEFT",
join_on_schema = "test_schema",
join_on_table = "test_table2",
join_on_column = "A")
```
or a full join:
```{r}
join1(conn = conn,
write_schema = "public",
data = test_data,
column = "A",
kind = "FULL",
join_on_schema = "test_schema",
join_on_table = "test_table2",
join_on_column = "A")
```
```{r, include=FALSE,eval=TRUE,results='hide'}
drop_schema(conn = conn,
schema = "test_schema",
cascade = TRUE)
dc(conn = conn)
```
## Code of Conduct
Please note that the pg13 project is released with a [Contributor Code of Conduct](https://contributor-covenant.org/version/2/0/CODE_OF_CONDUCT.html). By
contributing to this project, you agree to abide by its terms.