Method ResolveExisting

pkg/sql/sem/tree/name_resolution.go:270–329

ResolveExisting performs name resolution for a table name when the target object is expected to exist already.

(
	ctx context.Context,
	r TableNameExistingResolver,
	lookupFlags ObjectLookupFlags,
	curDb string,
	searchPath sessiondata.SearchPath,
)

// ResolveExisting performs name resolution for a table name when
// the target object is expected to exist already.
func (t *TableName) ResolveExisting(
	ctx context.Context,
	r TableNameExistingResolver,
	lookupFlags ObjectLookupFlags,
	curDb string,
	searchPath sessiondata.SearchPath,
) (bool, NameResolutionResult, error) {
	if t.ExplicitSchema {
		// pg_temp can be used as an alias for the current sessions temporary schema.
		// We must perform this resolution before looking up the object. This
		// resolution only succeeds if the session already has a temporary schema.
		scName, err := searchPath.MaybeResolveTemporarySchema(t.Schema())
		if err != nil {
			return false, nil, err
		}
		if t.ExplicitCatalog {
			// Already 3 parts: nothing to search. Delegate to the resolver.
			return r.LookupObject(ctx, lookupFlags, t.Catalog(), scName, t.Table())
		}
		// Two parts: D.T.
		// Try to use the current database, and be satisfied if it's sufficient to find the object.
		//
		// Note: we test this even if curDb == "", because CockroachDB
		// supports querying virtual schemas even when the current
		// database is not set. For example, `select * from
		// pg_catalog.pg_tables` is meant to show all tables across all
		// databases when there is no current database set.

		if found, objMeta, err := r.LookupObject(ctx, lookupFlags, curDb, scName, t.Table()); found || err != nil {
			if err == nil {
				t.CatalogName = Name(curDb)
			}
			return found, objMeta, err
		}
		// No luck so far. Compatibility with CockroachDB v1.1: try D.public.T instead.
		if found, objMeta, err := r.LookupObject(ctx, lookupFlags, t.Schema(), PublicSchema, t.Table()); found || err != nil {
			if err == nil {
				t.CatalogName = t.SchemaName
				t.SchemaName = PublicSchemaName
				t.ExplicitCatalog = true
			}
			return found, objMeta, err
		}
		// Welp, really haven't found anything.
		return false, nil, nil
	}

	// This is a naked table name. Use the search path.
	iter := searchPath.Iter()
	for next, ok := iter.Next(); ok; next, ok = iter.Next() {
		if found, objMeta, err := r.LookupObject(ctx, lookupFlags, curDb, next, t.Table()); found || err != nil {
			if err == nil {
				t.CatalogName = Name(curDb)
				t.SchemaName = Name(next)
			}
			return found, objMeta, err
		}
	}