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rlowdb

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rlowdb is a lightweight, JSON-based database for R, inspired by LowDB from JavaScript. It provides a simple and efficient way to store, retrieve, update, and delete structured data without the need for a full database system.

Features

Installation

rlowdb is not yet available on CRAN, but you can install it from GitHub:

devtools::install_github("feddelegrand7/rlowdb")

Usage

Initializing the Database

To start using `rlowdb``, create a new database instance by specifying a JSON file:

library(rlowdb)
db <- rlowdb$new("DB.json")

Inserting Data

The insert method takes two parameters, a collection and a record, think of the collection parameter as a table in the SQL world. Think of the record parameter as a list of names, each name/value pair representing a specific column and it’s value.

Add records to a collection:

db$insert(
  collection = "users", 
  record = list(id = 1, name = "Alice", age = 30)
)
db$insert(
  collection = "users", 
  record = list(id = 2, name = "Bob", age = 25)
)

db$insert(
  collection = "users", 
  record = list(id = 3, name = "Alice", age = 30)
)

Retrieving Data

Get all stored data:

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 30
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30

Find a specific record:

db$find(collection = "users", key = "id", value = 1)
#> [[1]]
#> [[1]]$id
#> [1] 1
#> 
#> [[1]]$name
#> [1] "Alice"
#> 
#> [[1]]$age
#> [1] 30

Updating Records

Modify existing records:

db$update(
  collection = "users", 
  key = "id", 
  value = 1, 
  new_data = list(age = 31)
)

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 31
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30

The upsert methods allows you to update a record if it exists, otherwise, it will be inserted:

db$upsert(
  collection = "users", 
  key = "id", 
  value = 1, 
  new_data = list(age = 25)
)

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 25
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30
db$upsert(
  collection = "users", 
  key = "id", 
  value = 100, 
  new_data = list(age = 25)
)

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 25
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30
#> 
#> 
#> $users[[4]]
#> $users[[4]]$id
#> [1] 100
#> 
#> $users[[4]]$age
#> [1] 25

Deleting Records

db$delete(collection = "users", key = "id", value = 100) 

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 25
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30

Querying Data

Find users older than 25:

db$query(collection = "users", condition = "age > 25")
#> [[1]]
#> [[1]]$id
#> [1] 3
#> 
#> [[1]]$name
#> [1] "Alice"
#> 
#> [[1]]$age
#> [1] 30

Query with multiple conditions:

db$query(collection = "users", condition = "age > 20 & id > 1")
#> [[1]]
#> [[1]]$id
#> [1] 2
#> 
#> [[1]]$name
#> [1] "Bob"
#> 
#> [[1]]$age
#> [1] 25
#> 
#> 
#> [[2]]
#> [[2]]$id
#> [1] 3
#> 
#> [[2]]$name
#> [1] "Alice"
#> 
#> [[2]]$age
#> [1] 30

Listing the collections

The list_collections method returns the names of the collections within your DB:

db$list_collections()
#> [1] "users"

Counting

Using the count method, you can get the number of records a collection has:

db$count(collection = "users") 
#> [1] 3

Check if exists

It possible to verify if a collection, a key or a value exists within your DB:

db$exists_collection(collection = "users")
#> [1] TRUE
db$exists_collection(collection = "nonexistant")
#> [1] FALSE
db$exists_key(collection = "users", key = "name")
#> [1] TRUE
db$exists_value(
  collection = "users",
  key = "name",
  value = "Alice"
)
#> [1] TRUE
db$exists_value(
  collection = "users",
  key = "name",
  value = "nonexistant"
)
#> [1] FALSE

Clear, Drop Data

It is possible to clear a collection. This will remove all the elements belonging to the collection but not drop the collection it self:

db$insert(collection = "countries", record = list(id = 1, country = "Algeria", continent = "Africa"))

db$insert(collection = "countries", record = list(id = 1, country = "Germany", continent = "Europe"))

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 25
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30
#> 
#> 
#> 
#> $countries
#> $countries[[1]]
#> $countries[[1]]$id
#> [1] 1
#> 
#> $countries[[1]]$country
#> [1] "Algeria"
#> 
#> $countries[[1]]$continent
#> [1] "Africa"
#> 
#> 
#> $countries[[2]]
#> $countries[[2]]$id
#> [1] 1
#> 
#> $countries[[2]]$country
#> [1] "Germany"
#> 
#> $countries[[2]]$continent
#> [1] "Europe"

Now, look what happened when we use the clear method on the countries collection:

db$clear("countries")

db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 25
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30
#> 
#> 
#> 
#> $countries
#> list()

Using the drop method, one can drop a whole collection:

db$drop(collection = "countries")
db$get_data()
#> $users
#> $users[[1]]
#> $users[[1]]$id
#> [1] 1
#> 
#> $users[[1]]$name
#> [1] "Alice"
#> 
#> $users[[1]]$age
#> [1] 25
#> 
#> 
#> $users[[2]]
#> $users[[2]]$id
#> [1] 2
#> 
#> $users[[2]]$name
#> [1] "Bob"
#> 
#> $users[[2]]$age
#> [1] 25
#> 
#> 
#> $users[[3]]
#> $users[[3]]$id
#> [1] 3
#> 
#> $users[[3]]$name
#> [1] "Alice"
#> 
#> $users[[3]]$age
#> [1] 30

Finally, drop_all will drop all the collections within your DB:

db$drop_all()
db$get_data()
#> named list()

Error Handling

rlowdb provides error handling for common issues. For example, attempting to update a collection that does not exist will result in an informative error:

db$update(
  collection = "nonexistant", 
  key = "id",
  value = 1, 
  new_data = list(age = 40)
)  
#> Error in private$.find_index_by_key(collection, key, value): Error: Collection 'nonexistant' does not exist.

Future Features

Code of Conduct

Please note that the ralger project is released with a Contributor Code of Conduct. By contributing to this project, you agree to abide by its terms.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.
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