Github user rdblue commented on a diff in the pull request:
https://github.com/apache/spark/pull/21978#discussion_r237585203
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/identifiers.scala ---
@@ -18,48 +18,106 @@
package org.apache.spark.sql.catalyst
/**
- * An identifier that optionally specifies a database.
+ * An identifier that optionally specifies a database and catalog.
*
* Format (unquoted): "name" or "db.name"
* Format (quoted): "`name`" or "`db`.`name`"
*/
-sealed trait IdentifierWithDatabase {
+sealed trait IdentifierWithOptionalDatabaseAndCatalog {
val identifier: String
def database: Option[String]
+ def catalog: Option[String]
+
/*
* Escapes back-ticks within the identifier name with double-back-ticks.
*/
private def quoteIdentifier(name: String): String = name.replace("`",
"``")
def quotedString: String = {
- val replacedId = quoteIdentifier(identifier)
- val replacedDb = database.map(quoteIdentifier(_))
-
- if (replacedDb.isDefined) s"`${replacedDb.get}`.`$replacedId`" else
s"`$replacedId`"
+ // database is required if catalog is present
+ assert(database.isDefined || catalog.isEmpty)
+ def q(s: String): String = s"`${quoteIdentifier(s)}`"
+ Seq(catalog.map(q), database.map(q),
Some(q(identifier))).flatten.mkString(".")
}
def unquotedString: String = {
- if (database.isDefined) s"${database.get}.$identifier" else identifier
+ Seq(catalog, database, Some(identifier)).flatten.mkString(".")
}
override def toString: String = quotedString
}
+object CatalogTableIdentifier {
+ def apply(table: String): CatalogTableIdentifier =
+ new CatalogTableIdentifier(table, None, None)
+
+ def apply(table: String, database: String): CatalogTableIdentifier =
+ new CatalogTableIdentifier(table, Some(database), None)
+
+ def apply(table: String, database: String, catalog: String):
CatalogTableIdentifier =
+ new CatalogTableIdentifier(table, Some(database), Some(catalog))
+}
+
/**
- * Identifies a table in a database.
- * If `database` is not defined, the current database is used.
- * When we register a permanent function in the FunctionRegistry, we use
- * unquotedString as the function name.
+ * Identifies a table in a database and catalog.
+ * If `database` is not defined, the current catalog's default database is
used.
+ * If `catalog` is not defined, the current catalog is used.
--- End diff --
No, we want to move away from a special global catalog. I think that Spark
should have a current catalog, like a current database, which is used to
resolve references that don't have an explicit catalog. That would have a
default, just like the current database has a default.
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