DBAbstractR: DBAbstractR
In PedroMiguelFMoreira/DBAbstractR: Database Abstracter

Description Usage Arguments Details Examples

Represents the abstraction layer between the user and the database. This object encapsulates both a database and an SQL query builder, allowing the extraction of information by simply calling functions. The only requirement is that the user knows what a relational database is and how tables reference each other when related.

dbAbstractR <- DBAbstractR$new()

dbAbstractR$connectToDatabase(TESTDSN)
# Every command below requires that the connection is established first.
dbAbstractR$listTables()
dbAbstractR$listTableInformation(tableName)
dbAbstractR$createView(viewName, tableMap, distinct, where, groupBy, having)
dbAbstractR$listViews()
dbAbstractR$deleteView(viewName)
dbAbstractR$createDataset(tableMap, distinct, where, groupBy, having)

dataSourceName: Data structure normally used to describe the connection to a database.
userID: Id of the user, usually necessary to perform database connections.
password: Password of the user, usually necessary to perform database connections.
tableName: Name of the table inside a database.
viewName: Name of the view inside a database.
tableMap: Dataframe specifing which tables and columns should be used to extract information.
distinct: Logical that dictates if the data retrieved should be distinct or not.
where: Filters the results by the specified conditions.
groupBy: Groups the results by the values of one or more columns.
having: Further filters the results, by allowing the use of agreggation functions (e.g. COUNT, SUM, ...)

$new() Creates an instance of DBAbstractR.

$connectToDatabase(dataSourceName = "", userID = "", password = "") Performs the connection to a database, returning its information.

$listTables Returns a dataframe with all the tables (name and description) in the database.

$listTableInformation(tableName = "") Returns a dataframe with the information (names of the columns, their type and nullability) about a given table.

$createView(viewName, tableMap, distinct = FALSE, where = "", groupBy = "", having = "") Creates a View in the database that can be used for further consultations. The contents of the View can be filtered results composed of one or more tables.

$listViews() Lists all the Views in a database.

$deleteView(viewName) Deletes a View from the database.

$createDataset(tableMap, distinct = FALSE, where = "", groupBy = "", having = "") Returns, from the database, the contents of a single table or a set of tables in the form of a dataframe. This results can be filtered or not.

## Not run: 
# Building the DBabstractR object.
dbAbstractR <- DBAbstractR$new()

# Connecting to a database.
dbAbstractR$connectToDatabase("TESTDSN")

## To perform the methods below, database connection is required.
# List all the tables in the database.
dbAbstractR$listTables()

# List all the information about a given table.
dbAbstractR$listTableInformation()

# Create a view from a table or a set of tables in the database.
dbAbstractR$createView(viewName, tableMap, distinct, where, groupBy, having)
---- TODO -----

# List all the views in the database.
dbAbstractR$listViews()

# Delete a view from the database.
dbAbstractR$deleteView(viewName)

# Create a dataset from a table or a set of tables in the database.
Please view the examples provided above in "$createView()", both methods work
the same way, the only difference is that a data frame is returned here. Also
this method can be used to consult Views, aswell as tables.

## End(Not run)