Package 'sqliter'

Functions to wrap SQLite calls

Description

sqliter helps users, mainly data munging practioneers, to organize their sql calls in a clean structure. It simplifies the process of extracting and transforming data into useful formats.

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lists databases into path

Description

lists databases into path

Usage

databases(object, filter = "")

## S3 method for class 'sqliter'
databases(object, filter = "")

Arguments

object	sqliter object
filter

Examples

DBM <- sqliter(path='data')
databases(DBM)
databases(DBM, 'fu')

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returns the paths of the given database

Description

returns the paths of the given database

Usage

find_database(object, database)

## S3 method for class 'sqliter'
find_database(object, database)

Arguments

object	sqliter object
database	the SQLite database filename without extension

Examples

## Not run: 
DBM <- sqliter(path=c("data", "another/project/data"))
find_database(DBM, "dummydatabase")
# "data/dummydatabase.db"

## End(Not run)

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execute query into a given database

Description

Once you have a sqliter database properly set you can execute queries into that database and get your data transformed. By default this function returns a data.frame object, but if you transform your data you can get whatever you need.

Usage

query(object, ...)

## S3 method for class 'sqliter'
query(object, database, query, post_proc = identity,
  index = 1, ...)

Arguments

object	sqliter object
...	additional arguments used by prepared queries
database	the SQLite database filename without extension
query	the query string
post_proc	a function to transform data, it receives a database and returns whatever you need.

Examples

## Not run: 
DBM <- sqliter(path=c("data", "another/project/data"))
ds <- query(DBM, "dummydatabase", "select count(*) from dummytable")
ds <- query(DBM, "dummydatabase", "select * from dummytable where
      name = :name", name=c("Macunamima", "Borba Gato"))
ds <- query(DBM, "dummydatabase", "select * from dummytable where
      name = :name", name=c("Macunamima", "Borba Gato"),
        post_proc=function(ds) {
ds <- transform(ds, birthday=as.Date(birthday))
ds
})

## End(Not run)

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query functions

Description

**query functions** are dynamic functions which connect to a database, execute queries in it and transform data. Actually it is a decorator for query function. query has 5 arguments. The first argument is an instance of the sqliter class and the second is the database name. The call to a query function is executed like a method call to the sqliter object through the $ operator. The function name must have the following pattern: query_<database name without extension>. This call returns an query function with the first 2 argument already set. The first parameter is the sqliter object on which the $ operator have been called and the second argument is extracted from the query function name, the name after the preffix query_.

Examples

## Not run: 
DBM <- sqliter(path=c("data", "another/project/data"))
DBM$query_dummydatabase("select count(*) from dummytable")

## End(Not run)

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Creates the sqliter a kinf of SQLite database manager, but not that far.

Description

sqliter object works pretty much like a database manager helping users to execute queries and transform data through a clean interface.

Usage

sqliter(path = ".", ...)

Arguments

...	arguments such as path must be provided during object instantiation.

Examples

## Not run: DBM <- sqliter(path=c("data", "another/project/data"))

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