From f8eee36ae16b0af4dde9c2891809f92833748021 Mon Sep 17 00:00:00 2001
From: Danijel Schorlemmer <ds@gfz-potsdam.de>
Date: Fri, 19 Mar 2021 23:58:51 +0100
Subject: [PATCH] Added initial Spatialite database class
---
Makefile | 2 +-
exposurelib/database.py | 84 +++++++++++++++++++++++++++++++++++++++++
2 files changed, 85 insertions(+), 1 deletion(-)
create mode 100644 exposurelib/database.py
diff --git a/Makefile b/Makefile
index 7ccccb8a..8b250680 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-SOURCES=exposurespatialite tests setup.py
+SOURCES=exposurelib tests setup.py
LENGTH=96
check: $(SOURCES)
diff --git a/exposurelib/database.py b/exposurelib/database.py
new file mode 100644
index 00000000..773cdb45
--- /dev/null
+++ b/exposurelib/database.py
@@ -0,0 +1,84 @@
+#!/usr/bin/env python3
+
+# Copyright (C) 2021:
+# Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ
+#
+# This program is free software: you can redistribute it and/or modify it
+# under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or (at
+# your option) any later version.
+#
+# This program is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Affero
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see http://www.gnu.org/licenses/.
+
+import logging
+import sqlite3
+
+
+logger = logging.getLogger(__name__)
+
+
+class SpatialiteDatabase:
+ """The SpatialiteDatabase class represents a Spatialite database. It manages the
+ database connection and cursor. Upon connection, the Spatialite extension is loaded.
+
+ Args:
+ database_filepath (str):
+ File path for the Spatialite database file.
+ spatialite_filepath (str):
+ File path of the Spatialite extension.
+
+ Attributes:
+ database_filepath (str):
+ Spatialite database file path.
+ spatialite_filepath (str):
+ File path to the Spatialite extension.
+ connection (sqlite3.Connection):
+ Database connection
+ cursor (sqlite3.Cursor):
+ Database cursor
+ """
+
+ def __init__(self, database_filepath, spatialite_filepath="mod_spatialite"):
+ self.database_filepath = database_filepath
+ self.spatialite_filepath = spatialite_filepath
+
+ self.connection = None
+ self.cursor = None
+
+ def connect(self, init_spatial_metadata=True):
+ """Connects to a database, loads the Spatialite extension and
+ initializes it if requested. If the database file does not exist,
+ it will be automatically created.
+
+ Args:
+ init_spatial_metadata (Bool):
+ Defines if the spatial metadata should be initialized. This is not
+ necessary if an existing Spatialite database is opened.
+ """
+
+ # Connect (if exists) or create SQLite database
+ logger.debug("Connecting to database at %s" % self.database_filepath)
+ self.connection = sqlite3.connect(self.database_filepath)
+ logger.debug("Connection to database established")
+
+ # Load and initialize the Spatialite extension
+ self.connection.enable_load_extension(True)
+ sql_statement = "SELECT load_extension('%s');" % self.spatialite_filepath
+ self.connection.execute(sql_statement)
+ if init_spatial_metadata:
+ self.connection.execute("SELECT InitSpatialMetaData(1);")
+ logger.debug("Spatialite extension loaded and initialized")
+
+ # Debug output
+ versions = self.connection.execute("SELECT sqlite_version(), spatialite_version()")
+ for row in versions:
+ logger.debug("SQLite version: %s" % row[0])
+ logger.debug("Spatialite version: %s" % row[1])
+
+ self.cursor = self.connection.cursor()
--
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