Database Visualization Support (#1582)

distribution/std-lib/Standard/src/Base/Data/Json.enso

@@ -117,8 +117,8 @@ type Marshalling_Error
     to_display_text : Text
     to_display_text = case this of
         Type_Mismatch_Error json format ->
-            json_text = Meta.type_to_display_text json
-            format_text = Meta.type_to_display_text format
+            json_text = Meta.get_simple_type_name json
+            format_text = Meta.get_simple_type_name format
             "Type mismatch error: the json with type `" + json_text + "` did not match the format `" + format_text + "`."
         Missing_Field_Error _ field _ ->
             "Missing field in Json: the field `" + field.to_text "` was missing in the json."

distribution/std-lib/Standard/src/Base/Meta.enso

@@ -148,9 +148,20 @@ get_source_location : Integer -> Text
 get_source_location skip_frames =
     Builtins.Meta.get_source_location skip_frames+1
 
-## Displays the type of the provided value as text.
+## PRIVATE
+
+   Displays the type of the provided value as text.
 
    Arguments:
    - value: The value for which to display the type.
-type_to_display_text : Any -> Text
-type_to_display_text value = Builtins.Meta.type_to_display_text value
+get_simple_type_name : Any -> Text
+get_simple_type_name value = Builtins.Meta.get_simple_type_name value
+
+## PRIVATE
+
+   Returns the fully qualified type name of the given value.
+
+   Arguments:
+   - value: the value to get the type of.
+get_qualified_type_name : Any -> Text
+get_qualified_type_name value = Builtins.Meta.get_qualified_type_name value

distribution/std-lib/Standard/src/Database/Connection/Connection.enso

@@ -69,7 +69,10 @@ type Connection
             ncols = metadata.getColumnCount
             column_names = Vector.new ncols ix-> metadata.getColumnName ix+1
             column_types = if expected_types.is_nothing.not then expected_types else
-                Vector.new ncols (ix -> Sql_Type <| metadata.getColumnType ix+1)
+                Vector.new ncols ix->
+                    typeid = metadata.getColumnType ix+1
+                    name = metadata.getColumnTypeName ix+1
+                    Sql_Type typeid name
             column_builders = column_types.map typ->
                 here.create_builder typ
             go has_next = if has_next.not then Nothing else
@@ -137,8 +140,9 @@ type Connection
             ncols = metadata.getColumnCount
             resolve_column ix =
                 name = metadata.getColumnName ix+1
-                typ = metadata.getColumnType ix+1
-                [name, Sql_Type typ]
+                typeid = metadata.getColumnType ix+1
+                typename = metadata.getColumnTypeName ix+1
+                [name, Sql_Type typeid typename]
             Vector.new ncols resolve_column
 
 ## PRIVATE

distribution/std-lib/Standard/src/Database/Data/Column.enso

@@ -459,6 +459,14 @@ type Aggregate_Column
     mean name_suffix='_mean' =
         here.make_aggregate this "AVG" name_suffix
 
+    ## PRIVATE
+
+       Helper that returns the underlying column from before grouping.
+    ungrouped : Column
+    ungrouped =
+        new_ctx = this.context.set_groups []
+        Column this.name this.connection this.sql_type this.expression new_ctx
+
 ## PRIVATE
 
    A helper method for creating an aggregated column by applying some

distribution/std-lib/Standard/src/Database/Data/Sql.enso

@@ -10,23 +10,28 @@ type Sql_Type
 
        Arguments:
        - typeid: a numerical type id, as defined in `java.sql.Types`.
-    type Sql_Type typeid
+       - name: a database-specific type name, used for pretty printing.
+    type Sql_Type typeid name
 
     ## The SQL representation of `Boolean` type.
     boolean : Sql_Type
-    boolean = Sql_Type Types.BOOLEAN
+    boolean = Sql_Type Types.BOOLEAN "BOOLEAN"
 
     ## The SQL representation of `Integer` type.
     integer : Sql_Type
-    integer = Sql_Type Types.INTEGER
+    integer = Sql_Type Types.INTEGER "INTEGER"
 
     ## The SQL type representing decimal numbers.
     decimal : Sql_Type
-    decimal = Sql_Type Types.DECIMAL
+    decimal = Sql_Type Types.DECIMAL "DECIMAL"
 
     ## The SQL type representing a general numeric type.
     numeric : Sql_Type
-    numeric = Sql_Type Types.NUMERIC
+    numeric = Sql_Type Types.NUMERIC "NUMERIC"
+
+    ## The SQL type representing one of the suppported textual types.
+    varchar : Sql_Type
+    varchar = Sql_Type Types.VARCHAR "VARCHAR"
 
     ## PRIVATE
 
@@ -42,7 +47,7 @@ type Sql_Type
        standard types so it may return false negatives for non-standard ones.
     is_definitely_boolean : Boolean
     is_definitely_boolean =
-        this.typeid == Types.BOOLEAN
+        [Types.BOOLEAN, Types.BIT].contains this.typeid
 
     ## PRIVATE
 
@@ -53,6 +58,12 @@ type Sql_Type
     is_definitely_double =
         [Types.FLOAT, Types.DOUBLE, Types.REAL].contains this.typeid
 
+    ## PRIVATE
+       Returns True if this type represents a Text.
+    is_definitely_text : Boolean
+    is_definitely_text =
+       [Types.VARCHAR, Types.LONGVARCHAR, Types.NVARCHAR, Types.LONGNVARCHAR].contains this.typeid
+
 ## UNSTABLE
 
    A fragment of a SQL query.
@@ -137,8 +148,8 @@ type Statement
     to_json =
         jsonify fragment = case fragment of
             Sql_Code_Part code -> Json.from_pairs [["sql_code", code]]
-            Sql_Interpolation (Sql_Type typeid) obj ->
-                inner = Json.from_pairs [["value", obj.to_json], ["typeid", typeid]]
+            Sql_Interpolation typ obj ->
+                inner = Json.from_pairs [["value", obj], ["expected_sql_type", typ.name]]
                 Json.from_pairs [["sql_interpolation", inner]]
         fragments = Json.Array (this.internal_fragments.map jsonify)
         Json.from_pairs [["query", fragments]]

distribution/std-lib/Standard/src/Database/Data/Table.enso

@@ -165,13 +165,22 @@ type Table
             turned_into_index.not
         this.updated_context new_ctx . updated_columns new_cols
 
-    ## Returns the index (or indexes) of this table, as a column (indexed by itself).
-       Returns `Nothing` if there is no index set.
-    index : Column | Vector Column | Nothing
+    ## UNSTABLE
+
+       Returns the (possibly empty) list of indices for this table.
+    indices : Vector Column
+    indices =
+        this.context.meta_index.map this.make_column
+
+    ## UNSTABLE
+
+       Returns the index (or indexes) of this table, as a column (indexed by itself).
+       Throws `No_Index_Set_Error` if there is no index set.
+    index : Column | Vector Column ! Materialized_Table.No_Index_Set_Error
     index =
-        ixes = this.context.meta_index.map this.make_column
-        len = this.context.meta_index.length
-        if len == 0 then Nothing else
+        ixes = this.indices
+        len = ixes.length
+        if len == 0 then Error.throw Materialized_Table.No_Index_Set_Error else
             if len == 1 then ixes.at 0 else ixes
 
     ## UNSTABLE
@@ -446,10 +455,7 @@ type Table
         count_columns = cols.map c-> IR.Internal_Column c.name Sql.Sql_Type.integer (IR.Operation "COUNT" [c.expression])
         count_table = this.updated_columns count_columns . to_dataframe
         counts = count_table.columns.map c-> c.at 0
-        column_type_as_text col =
-            id = col.sql_type.typeid
-            JDBCType.valueOf id . getName
-        types = cols.map column_type_as_text
+        types = cols.map c-> c.sql_type.name
         Materialized_Table.new [["Column", cols.map .name], ["Items Count", counts], ["SQL Type", types]] . set_index "Column"
 
     ## PRIVATE
@@ -540,6 +546,14 @@ type Aggregate_Table
     make_column internal =
         Aggregate_Column internal.name this.connection internal.sql_type internal.expression this.context
 
+    ## PRIVATE
+
+       Helper that returns the underlying table from before grouping.
+    ungrouped : Table
+    ungrouped =
+        new_ctx = this.context.set_groups []
+        Table this.name this.connection this.internal_columns new_ctx
+
 type Integrity_Error
     ## UNSTABLE
 

distribution/std-lib/Standard/src/Table/Data/Column.enso

@@ -222,10 +222,10 @@ type Column
     count = this.length - this.count_missing
 
     ## Returns the index of this column, as a column (indexed by itself).
-       Returns `Nothing` if there is no index set.
-    index : Column | Nothing
+       Throws `No_Index_Set_Error` if there is no index set.
+    index : Column ! Table.No_Index_Set_Error
     index = case this.java_column.getIndex.toColumn of
-        Nothing -> Nothing
+        Nothing -> Error.throw Table.No_Index_Set_Error
         i -> Column i
 
     ## Returns the item contained in this column at the given index.
@@ -378,6 +378,13 @@ type Column
         new_col = this.java_column.applyMask mask
         Column new_col
 
+    ## UNSTABLE
+
+       Returns a column truncated to at most `max_rows` rows.
+    take_start : Integer -> Column
+    take_start max_rows =
+        Column (this.java_column.slice 0 max_rows)
+
 ## Creates a new column given a name and a vector of elements.
 from_vector : Text -> Vector -> Column
 from_vector name items = Column (Java_Column.fromItems name items.to_array)

distribution/std-lib/Standard/src/Table/Data/Table.enso

@@ -12,6 +12,9 @@ polyglot java import org.enso.table.operations.OrderBuilder
 ## An error returned when a non-existent column is being looked up.
 type No_Such_Column_Error column_name
 
+## An error returned when getting an index but no index is set for that table.
+type No_Index_Set_Error
+
 ## Represents a column-oriented table data structure.
 type Table
     type Table java_table
@@ -108,10 +111,10 @@ type Table
         Table (this.java_table.indexFromColumn index)
 
     ## Returns the index of this table, as a column (indexed by itself).
-       Returns `Nothing` if there is no index set.
-    index : Column.Column | Nothing
+       Throws `No_Index_Set_Error` if there is no index set.
+    index : Column.Column ! No_Index_Set_Error
     index = case this.java_table.getIndex.toColumn of
-        Nothing -> Nothing
+        Nothing -> Error.throw No_Index_Set_Error
         i -> Column.Column i
 
     ## Selects a subset of columns from this table by name.
@@ -306,6 +309,13 @@ type Table
     concat other =
         Table (this.java_table.concat other.java_table)
 
+    ## UNSTABLE
+
+       Returns a table truncated to at most `max_rows` rows.
+    take_start : Integer -> Table
+    take_start max_rows =
+        Table (this.java_table.slice 0 max_rows)
+
 ## PRIVATE
 comparator_to_java cmp x y = cmp x y . to_sign
 

distribution/std-lib/Standard/src/Test.enso

@@ -93,20 +93,25 @@ Error.should_equal _ = Panic.throw (Matched_On_Error this)
 Decimal.should_equal that (epsilon = 0) = case this.equals that epsilon of
     True -> Success
     False ->
-        msg = this.to_text + " did not equal " + that.to_text + "."
+        loc = Meta.get_source_location 2
+        msg = this.to_text + " did not equal " + that.to_text + " (at " + loc + ")."
         Panic.throw (Failure msg)
 
 ## Asserts that the given `Boolean` is `True`
 Boolean.should_be_true = case this of
     True -> Success
-    False -> Panic.throw (Failure "Expected False to be True.")
+    False ->
+        loc = Meta.get_source_location 2
+        Panic.throw (Failure "Expected False to be True (at "+loc+").")
 
 ## Asserts that the given `Boolean` is `True`.
 Error.should_be_true = Panic.throw (Matched_On_Error this)
 
 ## Asserts that the given `Boolean` is `False`
 Boolean.should_be_false = case this of
-    True -> Panic.throw (Failure "Expected True to be False.")
+    True ->
+        loc = Meta.get_source_location 2
+        Panic.throw (Failure "Expected True to be False (at "+loc+").")
     False -> Success
 
 ## Asserts that the given `Boolean` is `False`

distribution/std-lib/Standard/src/Visualization/Helpers.enso

@@ -0,0 +1,8 @@
+from Standard.Base import all
+
+## PRIVATE
+recover_errors ~body =
+    result = Panic.recover body
+    result.catch err->
+        Json.from_pairs [["error", err.to_display_text]] . to_text
+

distribution/std-lib/Standard/src/Visualization/Sql/Visualization.enso

@@ -0,0 +1,39 @@
+from Standard.Base import all
+
+import Standard.Visualization.Helpers
+
+## PRIVATE
+
+   Prepares the query for visualization.
+
+   For each interpolation it provides its value, its actual type name, its
+   expected SQL type name and if it was possible to infer it, its expected Enso
+   typename.
+
+   Expected Enso types are inferred based on known SQL types and their mapping
+   to Enso types.
+prepare_visualization x = Helpers.recover_errors <|
+    prepared = x.to_sql.prepare
+    code = prepared.first
+    interpolations = prepared.second
+    mapped = interpolations.map e->
+        value = e.first
+        actual_type = Meta.get_qualified_type_name value
+        expected_sql_type = e.second.name
+        expected_enso_type = here.find_expected_enso_type_for_sql e.second
+        Json.from_pairs [["value", value], ["actual_type", actual_type], ["expected_sql_type", expected_sql_type], ["expected_enso_type", expected_enso_type]]
+    dialect = x.connection.dialect.name
+    Json.from_pairs [["dialect", dialect], ["code", code], ["interpolations", mapped]] . to_text
+
+## PRIVATE
+
+   Return an expected Enso type for an SQL type.
+
+   Expected Enso types are only inferred for some known SQL types. For unknown
+   types it will return `Nothing`.
+find_expected_enso_type_for_sql sql_type =
+    if sql_type.is_definitely_integer then "Builtins.Main.Integer" else
+        if sql_type.is_definitely_double then "Builtins.Main.Decimal" else
+            if sql_type.is_definitely_text then "Builtins.Main.Text" else
+                if sql_type.is_definitely_boolean then "Builtins.Main.Boolean" else
+                    Nothing