Diagnose a join before executing

Analyzes join cardinality without performing the full join. Useful for detecting many-to-many joins that would explode row count.

Usage

diagnose_join(x, y, by = NULL, use_joinspy = TRUE)

Arguments

x

Left data frame.

y

Right data frame.

by

Join specification.

use_joinspy

If TRUE (default), use joinspy for enhanced diagnostics when available. Set to FALSE to use built-in diagnostics only.

Value

A list with cardinality information, or a JoinReport object if joinspy is used.

Details

If the joinspy package is installed, this function delegates to joinspy::join_spy() for enhanced diagnostics including whitespace detection, encoding issues, and detailed match analysis.

See also

joinspy::join_spy() for enhanced diagnostics (if installed)

Examples

x <- data.frame(id = c(1, 1, 2), a = 1:3)
y <- data.frame(id = c(1, 1, 2), b = 4:6)
diagnose_join(x, y, by = "id", use_joinspy = FALSE)