rules.go

package analyzer

import (
	errors "gopkg.in/src-d/go-errors.v1"
)

// DefaultRules to apply when analyzing nodes.
var DefaultRules = []Rule{
	{"resolve_natural_joins", resolveNaturalJoins},
	{"resolve_orderby_literals", resolveOrderByLiterals},
	{"resolve_orderby", resolveOrderBy},
	{"resolve_grouping_columns", resolveGroupingColumns},
	{"qualify_columns", qualifyColumns},
	{"resolve_columns", resolveColumns},
	{"resolve_database", resolveDatabase},
	{"resolve_star", resolveStar},
	{"resolve_functions", resolveFunctions},
	{"reorder_aggregations", reorderAggregations},
	{"reorder_projection", reorderProjection},
	{"move_join_conds_to_filter", moveJoinConditionsToFilter},
	{"eval_filter", evalFilter},
	{"optimize_distinct", optimizeDistinct},
}

// OnceBeforeDefault contains the rules to be applied just once before the
// DefaultRules.
var OnceBeforeDefault = []Rule{
	{"resolve_subqueries", resolveSubqueries},
	{"resolve_tables", resolveTables},
}

// OnceAfterDefault contains the rules to be applied just once after the
// DefaultRules.
var OnceAfterDefault = []Rule{
	{"remove_unnecessary_converts", removeUnnecessaryConverts},
	{"assign_catalog", assignCatalog},
	{"prune_columns", pruneColumns},
	{"pushdown", pushdown},
	{"erase_projection", eraseProjection},
}

// OnceAfterAll contains the rules to be applied just once after all other
// rules have been applied.
var OnceAfterAll = []Rule{
	{"track_process", trackProcess},
	{"parallelize", parallelize},
	{"clear_warnings", clearWarnings},
}

var (
	// ErrColumnTableNotFound is returned when the column does not exist in a
	// the table.
	ErrColumnTableNotFound = errors.NewKind("table %q does not have column %q")
	// ErrColumnNotFound is returned when the column does not exist in any
	// table in scope.
	ErrColumnNotFound = errors.NewKind("column %q could not be found in any table in scope")
	// ErrAmbiguousColumnName is returned when there is a column reference that
	// is present in more than one table.
	ErrAmbiguousColumnName = errors.NewKind("ambiguous column name %q, it's present in all these tables: %v")
	// ErrFieldMissing is returned when the field is not on the schema.
	ErrFieldMissing = errors.NewKind("field %q is not on schema")
	// ErrOrderByColumnIndex is returned when in an order clause there is a
	// column that is unknown.
	ErrOrderByColumnIndex = errors.NewKind("unknown column %d in order by clause")
	// ErrMisusedAlias is returned when a alias is defined and used in the same projection.
	ErrMisusedAlias = errors.NewKind("column %q does not exist in scope, but there is an alias defined in" +
		" this projection with that name. Aliases cannot be used in the same projection they're defined in")
)