Applies the joins in accordance to a relationship schema.

This function pulls the system table within an Access database that dictates the join order and types. It will then attempt to apply those joining rules to the provided tables. Users can specify which tables they would like to join through the tables that they provide the function. Ensure that the names of the tables provided matches those required in the relationship table.

Usage

schemaJoin(schema, data)

Arguments

schema: A schema table that mirrors the structure of an Access schema.
data: A list of data tables to be joined

Value

A data frame joined according to the relationship schema.

Details

The join type in the relationship table from Access can be modified directly if required. Simply add a joinType column to the relationship table and specify one of four options: full_join, inner_join, left_join, or right_join. The data argument can theoretically take in any data frame. This allows for manipulations of the relational tables if such operations are necessary before joining. Within the schema table itself, szReferencedObject refers to the relational table with the primary key, while szObject refers to the relational table with the foreign key.

Note

The tables in the 20mm dataset aren't sequentially linked. There are tables that are linked together first before being linked back to the original. How do I solve this?

Examples

if (FALSE) { # \dontrun{
slsTables <- bridgeAccess(
"https://filelib.wildlife.ca.gov/Public/Delta%20Smelt/SLS.zip",
tables = c("Catch", "FishCodes", "Lengths", "Meter Corrections",
"SLS Stations", "Tow Info", "Water Info")
)

schema <- bridgeAccess(
"https://filelib.wildlife.ca.gov/Public/Delta%20Smelt/SLS.zip",
tables = c("MSysRelationships"))[[1]]

schemaJoin(schema, slsTables)
} # }