compute_from_db: Compute data from Database

In VwGHat: Mining Austrian administrative court rulings

Description

This function applys mining functions to the database, conveniently wrapping all database interactions.

Usage

compute_from_db(con, func, table_name, fields_in, fields_out, field_types="TEXT",
		table_setup=setup_foreign_table, include_foreign_key=TRUE, limit=0)

Arguments

con	The database connection.
func	The mining function. It is called with func(df), where df is a one-row data.frame with colums defined in fields\_in; should return a list with elements defined in fields\_out, all elements must have the same length (typically 1).
table_name	Name of the table to be set up in the DB.
fields_in	Fields from the db main table (Rechtsinformationssystem) to feed in the mining function (Note: SP\_Nr is always passed along).
fields_out	Fields to to create in the new table.
field_types	Format of the table cells. You may supply a vector of formats. Default = 'Text'
table_setup	Function called to create the table. Use this if you need custom table creation, or supply an empty function to create no table at all (The table table\_name has to be present in the database). See the setup_foreign_table on how this function is called.
include_foreign_key	Incude the foreign key (SP\_Nr) in the new table?
limit	Database record limit. 0 means no limit.

Details

compute\_from\_db is a wrapper to the database created by build\_RIS\_db. Use this to easily create your own mining functions. The function will call the miner once per database record with a single-row dataframe containing the fields in fields\_out and expects a list with fields\_in. This list is treated as a dateframe and written to the db, together with SP\_Nr unless you specified otherwise (see above). This means you can return more then one row per ruling. All database interaction is done by this function.

Author(s)

Martin Kober <[e-mail]>, Georg M. Zajko <[e-mail]>

VwGHat documentation built on May 2, 2019, 5:55 p.m.