Add tableNames.

python/pyspark/sql/context.py

@@ -622,7 +622,7 @@ def table(self, tableName):
         return DataFrame(self._ssql_ctx.table(tableName), self)
 
     def tables(self, dbName=None):
-        """Returns a DataFrame containing names of table in the given database.
+        """Returns a DataFrame containing names of tables in the given database.
 
         If `dbName` is not specified, the current database will be used.
 
@@ -639,6 +639,22 @@ def tables(self, dbName=None):
         else:
             return DataFrame(self._ssql_ctx.tables(dbName), self)
 
+    def tableNames(self, dbName=None):
+        """Returns a list of names of tables in the database `dbName`.
+
+        If `dbName` is not specified, the current database will be used.
+
+        >>> sqlCtx.registerRDDAsTable(df, "table1")
+        >>> "table1" in sqlCtx.tableNames()
+        True
+        >>> "table1" in sqlCtx.tableNames("db")
+        True
+        """
+        if dbName is None:
+            return [name for name in self._ssql_ctx.tableNames()]
+        else:
+            return [name for name in self._ssql_ctx.tableNames(dbName)]
+
     def cacheTable(self, tableName):
         """Caches the specified table in-memory."""
         self._ssql_ctx.cacheTable(tableName)

sql/core/src/main/scala/org/apache/spark/sql/SQLContext.scala

@@ -734,6 +734,15 @@ class SQLContext(@transient val sparkContext: SparkContext)
   def table(tableName: String): DataFrame =
     DataFrame(this, catalog.lookupRelation(Seq(tableName)))
 
+  /**
+   * Returns a [[DataFrame]] containing names of existing tables in the given database.
+   * The returned DataFrame has two columns, tableName and isTemporary (a column with BooleanType
+   * indicating if a table is a temporary one or not).
+   */
+  def tables(): DataFrame = {
+    createDataFrame(catalog.getTables(None)).toDataFrame("tableName", "isTemporary")
+  }
+
   /**
    * Returns a [[DataFrame]] containing names of existing tables in the current database.
    * The returned DataFrame has two columns, tableName and isTemporary (a column with BooleanType
@@ -744,12 +753,21 @@ class SQLContext(@transient val sparkContext: SparkContext)
   }
 
   /**
-   * Returns a [[DataFrame]] containing names of existing tables in the given database.
-   * The returned DataFrame has two columns, tableName and isTemporary (a column with BooleanType
-   * indicating if a table is a temporary one or not).
+   * Returns an array of names of tables in the current database.
    */
-  def tables(): DataFrame = {
-    createDataFrame(catalog.getTables(None)).toDataFrame("tableName", "isTemporary")
+  def tableNames(): Array[String] = {
+    catalog.getTables(None).map {
+      case (tableName, _) => tableName
+    }.toArray
+  }
+
+  /**
+   * Returns an array of names of tables in the given database.
+   */
+  def tableNames(databaseName: String): Array[String] = {
+    catalog.getTables(Some(databaseName)).map {
+      case (tableName, _) => tableName
+    }.toArray
   }
 
   protected[sql] class SparkPlanner extends SparkStrategies {