Example - SQL#
This section shows examples that execute a simple SQL in multiple ways.
Raw C API from C#
The following code shows how to execute a simple SQL with raw C API in C. Here are points:
You can create a session context (
DFSessionContext) bydf_session_context_new().You can run a SQL by
df_session_context_sql().You can get details on error by
DFError. See alsodf_error_get_code()anddf_error_get_message().You need to free
DFErrorbydf_error_free()when no longer needed.You can get
DFDataFrameas a result of the SQL execution.You can show
DFDataFramecontents bydf_data_frame_show().You can free
DFDataFramebydf_data_frame_free().You can free
DFSessionContextbydf_session_context_free().
1/*
2 * Copyright 2022 Sutou Kouhei <kou@clear-code.com>
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 */
15
16/*
17 * How to build:
18 * $ cc -o sql sql.c $(pkg-config --cflags --libs datafusion)
19 *
20 * How to run:
21 * $ ./sql
22 * +----------+
23 * | Int64(1) |
24 * +----------+
25 * | 1 |
26 * +----------+
27 */
28
29#include <datafusion.h>
30
31#include <stdio.h>
32#include <stdlib.h>
33
34int
35main(void)
36{
37 DFSessionContext *context = df_session_context_new();
38 DFError *error = NULL;
39 DFDataFrame *data_frame = df_session_context_sql(context, "SELECT 1;", &error);
40 if (error) {
41 printf("failed to run SQL: %s\n", df_error_get_message(error));
42 df_error_free(error);
43 df_session_context_free(context);
44 return EXIT_FAILURE;
45 }
46 df_data_frame_show(data_frame, &error);
47 if (error) {
48 printf("failed to show data frame: %s\n", df_error_get_message(error));
49 df_error_free(error);
50 }
51 df_data_frame_free(data_frame);
52 df_session_context_free(context);
53 return EXIT_SUCCESS;
54}
GLib API from C#
The following code shows how to execute a simple SQL with GLib API in C. Here are points:
You can create a session context (GDFSessionContext) by gdf_session_context_new().
You can run a SQL by gdf_session_context_sql().
You can handle error the usual way in GLib. See GError.
You can get GDFDataFrame as a result of the SQL execution.
You can show GDFDataFrame contents by gdf_data_frame_show().
You can free all GObject based objects such as GDFSessionContext and GDFDataFrame by g_object_unref().
1/*
2 * Copyright 2022 Sutou Kouhei <kou@clear-code.com>
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 */
15
16/*
17 * How to build:
18 * $ cc -o sql-glib sql-glib.c $(pkg-config --cflags --libs datafusion-glib)
19 *
20 * How to run:
21 * $ ./sql-glib
22 * +----------+
23 * | Int64(1) |
24 * +----------+
25 * | 1 |
26 * +----------+
27 */
28
29#include <datafusion-glib/datafusion-glib.h>
30
31#include <stdlib.h>
32
33int
34main(void)
35{
36 GDFSessionContext *context = gdf_session_context_new();
37 GError *error = NULL;
38 GDFDataFrame *data_frame = gdf_session_context_sql(context,
39 "SELECT 1;",
40 &error);
41 if (error) {
42 g_print("failed to run SQL: %s\n", error->message);
43 g_error_free(error);
44 g_object_unref(context);
45 return EXIT_FAILURE;
46 }
47 gdf_data_frame_show(data_frame, &error);
48 if (error) {
49 g_print("failed to show data frame: %s\n", error->message);
50 g_error_free(error);
51 }
52 g_object_unref(data_frame);
53 g_object_unref(context);
54 return EXIT_SUCCESS;
55}
Raw C API from Python#
The following code shows how to execute a simple SQL with raw C API in Python. You can use a FFI library such as ctypes to use raw C API from Python. Here are points:
You need to open DataFusion C’s shared library explicitly but shared library name depends on platform. For example, it’s
libdatafusion.soon Linux.ctypes.util.find_library()may help you.You need to open DataFusion C’s shared library by
ctypes.CDLL().You need to prepare signature of raw C API’s functions that you need to use before you call them.
See Raw C API from C how to use raw C API.
1#!/usr/bin/env python3
2#
3# Copyright 2022 Sutou Kouhei <kou@clear-code.com>
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9# http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17# How to run:
18# $ ./sql.py
19# +----------+
20# | Int64(1) |
21# +----------+
22# | 1 |
23# +----------+
24
25import ctypes
26import ctypes.util
27
28datafusion_so_path = ctypes.util.find_library('datafusion')
29if datafusion_so_path is None:
30 import sys
31 if sys.platform == 'darwin':
32 datafusion_so_path = 'libdatafusion.dylib'
33 elif sys.platform == 'win32':
34 datafusion_so_path = 'datafusion.dll'
35 else:
36 datafusion_so_path = 'libdatafusion.so'
37datafusion = ctypes.CDLL(datafusion_so_path)
38
39datafusion.df_error_free.argtypes = [ctypes.c_void_p]
40datafusion.df_error_free.restype = None
41datafusion.df_error_get_message.argtypes = [ctypes.c_void_p]
42datafusion.df_error_get_message.restype = ctypes.c_char_p
43
44datafusion.df_session_context_new.argtypes = []
45datafusion.df_session_context_new.restype = ctypes.c_void_p
46datafusion.df_session_context_free.argtypes = [ctypes.c_void_p]
47datafusion.df_session_context_free.restype = None
48datafusion.df_session_context_sql.argtypes = \
49 [ctypes.c_void_p, ctypes.c_char_p, ctypes.c_void_p]
50datafusion.df_session_context_sql.restype = ctypes.c_void_p
51
52datafusion.df_data_frame_free.argtypes = [ctypes.c_void_p]
53datafusion.df_data_frame_free.restype = None
54datafusion.df_data_frame_show.argtypes = [ctypes.c_void_p, ctypes.c_void_p]
55datafusion.df_data_frame_show.restype = None
56
57context = datafusion.df_session_context_new()
58try:
59 error = (ctypes.c_void_p * 1)()
60 try:
61 data_frame = datafusion.df_session_context_sql(
62 context, b'SELECT 1;', ctypes.pointer(error))
63 if error[0] is not None:
64 message = datafusion.df_error_get_message(error[0])
65 print(f'failed to run SQL: {message.decode()}')
66 exit(1)
67 try:
68 datafusion.df_data_frame_show(data_frame, ctypes.pointer(error));
69 if error[0] is not None:
70 message = datafusion.df_error_get_message(error[0])
71 print('failed to show data frame: {message.decode()}')
72 exit(1)
73 finally:
74 datafusion.df_data_frame_free(data_frame)
75 finally:
76 if error[0] is not None:
77 datafusion.df_error_free(error[0])
78finally:
79 datafusion.df_session_context_free(context)
GLib API from Python#
The following code shows how to execute a simple SQL with GLib API in Python. You can use PyGObject to use GLib API from Python. Here are points:
You can use
DataFusionas GObject Introspection namespace.See GLib API from C how to use GLib API.
1#!/usr/bin/env python3
2#
3# Copyright 2022 Sutou Kouhei <kou@clear-code.com>
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9# http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17# How to run:
18# $ ./sql-glib.py
19# +----------+
20# | Int64(1) |
21# +----------+
22# | 1 |
23# +----------+
24
25import gi
26from gi.repository import DataFusion
27
28context = DataFusion.SessionContext.new()
29data_frame = context.sql("SELECT 1;", )
30data_frame.show()
Raw C API from Ruby#
The following code shows how to execute a simple SQL with raw C API in Ruby. You can use a FFI library such as Fiddle to use raw C API from Ruby. Here are points:
You need to open DataFusion C’s shared library explicitly but shared library name depends on platform. For example, it’s
libdatafusion.soon Linux.RbConfig::CONFIG["SOEXT"]may help you.You need to open DataFusion C’s shared library by
Fiddle::Importer.dlload.You need to register raw C API’s functions that you need to use explicitly before you call them.
See Raw C API from C how to use raw C API.
1#!/usr/bin/env ruby
2#
3# Copyright 2022 Sutou Kouhei <kou@clear-code.com>
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9# http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17# How to run:
18# $ ./sql.rb
19# +----------+
20# | Int64(1) |
21# +----------+
22# | 1 |
23# +----------+
24
25require "rbconfig"
26require "fiddle/import"
27
28module DataFusion
29 extend Fiddle::Importer
30
31 ext = RbConfig::CONFIG["SOEXT"]
32 if /mingw|mswin/.match?(RUBY_PLATFORM)
33 prefix = ""
34 else
35 prefix = "lib"
36 end
37 dlload "#{prefix}datafusion.#{ext}"
38
39 typealias "DFError *", "void *"
40 extern "void df_error_free(DFError *error)"
41 extern "const char *df_error_get_message(DFError *error)"
42
43 typealias "DFDataFrame *", "void *"
44 extern "void df_data_frame_free(DFDataFrame *data_frame)"
45 extern "void df_data_frame_show(DFDataFrame *data_frame, DFError **error)"
46
47 typealias "DFSessionContext *", "void *"
48 extern "DFSessionContext *df_session_context_new(void)"
49 extern "void df_session_context_free(DFSessionContext *ctx)"
50 extern "DFDataFrame *df_session_context_sql(DFSessionContext *ctx, const char *sql, DFError **error)"
51end
52
53begin
54 context = DataFusion.df_session_context_new
55 Fiddle::Pointer.malloc(Fiddle::SIZEOF_VOIDP, Fiddle::RUBY_FREE) do |error|
56 begin
57 data_frame = DataFusion.df_session_context_sql(context, "SELECT 1;", error)
58 unless error.ptr.null?
59 message = DataFusion.df_error_get_message(error.ptr)
60 puts("failed to run SQL: #{message}")
61 exit(false)
62 end
63 begin
64 DataFusion.df_data_frame_show(data_frame, error)
65 unless error.ptr.null?
66 message = DataFusion.df_error_get_message(error.ptr)
67 puts("failed to show data frame: #{message}")
68 exit(false)
69 end
70 ensure
71 DataFusion.df_data_frame_free(data_frame)
72 end
73 ensure
74 DataFusion.df_error_free(error.ptr) unless error.ptr.null?
75 end
76 end
77ensure
78 DataFusion.df_session_context_free(context)
79end
GLib API from Ruby#
The following code shows how to execute a simple SQL with GLib API in Ruby. You can use gobject-introspection gem or red-datafusion gem to use GLib API from Ruby. The following example uses gobject-introspection gem but you should use red-datafusion gem in production. red-datafusion gem is built on top of the gobject-introspection gem and adds many useful APIs. Here are points:
You can use
DataFusionas GObject Introspection namespace.See GLib API from C how to use GLib API.
1#!/usr/bin/env ruby
2#
3# Copyright 2022 Sutou Kouhei <kou@clear-code.com>
4#
5# Licensed under the Apache License, Version 2.0 (the "License");
6# you may not use this file except in compliance with the License.
7# You may obtain a copy of the License at
8#
9# http://www.apache.org/licenses/LICENSE-2.0
10#
11# Unless required by applicable law or agreed to in writing, software
12# distributed under the License is distributed on an "AS IS" BASIS,
13# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
14# See the License for the specific language governing permissions and
15# limitations under the License.
16
17# How to run:
18# $ ./sql-glib.rb
19# +----------+
20# | Int64(1) |
21# +----------+
22# | 1 |
23# +----------+
24
25require "gi"
26
27DataFusion = GI.load("DataFusion")
28
29context = DataFusion::SessionContext.new
30data_frame = context.sql("SELECT 1;")
31data_frame.show
GLib API from Vala#
The following code shows how to execute a simple SQL with GLib API in
Vala. You need to add -Dvapi=true when you run meson setup to
enable Vala support. Here are points:
You can use
datafusion-glibas Vala package name.You can get a directory where Vala API file for
datafusion-glibpackage exists bypkg-config --variable=vapidir datafusion-glib.See GLib API from C how to use GLib API.
1// Copyright 2022 Sutou Kouhei <kou@clear-code.com>
2//
3// Licensed under the Apache License, Version 2.0 (the "License");
4// you may not use this file except in compliance with the License.
5// You may obtain a copy of the License at
6//
7// http://www.apache.org/licenses/LICENSE-2.0
8//
9// Unless required by applicable law or agreed to in writing, software
10// distributed under the License is distributed on an "AS IS" BASIS,
11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12// See the License for the specific language governing permissions and
13// limitations under the License.
14
15// How to build:
16// $ valac \
17// --vapidir $(pkg-config --variable=vapidir datafusion-glib) \
18// --pkg datafusion-glib \
19// --pkg posix \
20// sql-glib.vala
21//
22// How to run:
23// $ ./sql-glib
24// +----------+
25// | Int64(1) |
26// +----------+
27// | 1 |
28// +----------+
29
30int main(string[] args) {
31 var context = new GDF.SessionContext();
32 GDF.DataFrame data_frame;
33 try {
34 data_frame = context.sql("SELECT 1;");
35 } catch (Error error) {
36 stderr.printf("failed to run SQL: %s\n", error.message);
37 return Posix.EXIT_FAILURE;
38 }
39 try {
40 data_frame.show();
41 } catch (Error error) {
42 stderr.printf("failed to show data frame: %s\n", error.message);
43 return Posix.EXIT_FAILURE;
44 }
45 return Posix.EXIT_SUCCESS;
46}