fix: add measured values table - sqlite

.drone.yml

@@ -13,17 +13,21 @@ steps:
     - pull_request
     - tag
 
-- name: trigger
-  image: plugins/downstream
-  settings:
-    server: https://drone.cryptic.systems
-    token:
-      from_secret: drone_token
-    params:
-    - VERSION=${DRONE_COMMIT_HASH}
-    fork: true
-    repositories:
-    - flucky/PKGBUILD@master
+# - name: golangci-lint
+#   image: docker.io/golangci/golangci-lint:v1.40.1-alpine
+#   commands:
+#   - golangci-lint run --concurrency $(nproc --ignore=1)
+#   when:
+#     event:
+#     - push
+#     - pull_request
+
+# - name: gosec
+#   image: docker.io/securego/gosec:v2.8.0
+#   when:
+#     event:
+#     - push
+#     - pull_request
 
 # steps:
 # - name: test-unit

.gitignore

@@ -1,7 +1,8 @@
 # absolute files
-bin
 .env
 
+flucky*
+
 # directories
 .vscode/
 

Makefile

@@ -7,42 +7,9 @@ PREFIX?=/usr/local
 
 # BINARIES
 # ==============================================================================
-EXECUTABLE_TARGETS:= \
-	bin/linux/amd64/${EXECUTABLE} \
-	bin/linux/arm/5/${EXECUTABLE} \
-	bin/linux/arm/7/${EXECUTABLE} \
-	bin/tmp/${EXECUTABLE}
+all: ${EXECUTABLE}
 
-${EXECUTABLE}: bin/tmp/${EXECUTABLE}
-
-bin/linux/amd64/${EXECUTABLE}:
-	CGO_ENABLED=1 \
-	GOOS=linux \
-	GOARCH=amd64 \
-	GOPROXY=$(shell go env GOPROXY) \
-	GOPRIVATE=$(shell go env GOPRIVATE) \
-		go build -ldflags "-X main.version=${VERSION:v%=%}" -o ${@}
-
-bin/linux/arm/5/${EXECUTABLE}:
-	CGO_ENABLED=1 \
-	GOOS=linux \
-	GOARCH=arm \
-	GOARM=5 \
-	GOPROXY=$(shell go env GOPROXY) \
-	GOPRIVATE=$(shell go env GOPRIVATE) \
-		go build -ldflags "-X main.version=${VERSION:v%=%}" -o ${@}
-
-bin/linux/arm/7/${EXECUTABLE}:
-	CC=arm-linux-gnueabihf-gcc \
-	CGO_ENABLED=1 \
-	GOOS=linux \
-	GOARCH=arm \
-	GOARM=7 \
-	GOPROXY=$(shell go env GOPROXY) \
-	GOPRIVATE=$(shell go env GOPRIVATE) \
-		go build -ldflags "-X main.version=${VERSION:v%=%}" -o ${@}
-
-bin/tmp/${EXECUTABLE}:
+${EXECUTABLE}:
 	CGO_ENABLED=1 \
 	GOPROXY=$(shell go env GOPROXY) \
 	GOPRIVATE=$(shell go env GOPRIVATE) \
@@ -50,48 +17,48 @@ bin/tmp/${EXECUTABLE}:
 
 # COMPLETIONS
 # ==============================================================================
-bin/tmp/${EXECUTABLE}.sh: bin/tmp/${EXECUTABLE}
-	bin/tmp/${EXECUTABLE} completion bash > ${@}
+${EXECUTABLE}.sh: ${EXECUTABLE}
+	${EXECUTABLE} completion bash > ${@}
 
-bin/tmp/${EXECUTABLE}.fish: bin/tmp/${EXECUTABLE}
-	bin/tmp/${EXECUTABLE} completion fish > ${@}
+${EXECUTABLE}.fish: ${EXECUTABLE}
+	${EXECUTABLE} completion fish > ${@}
 
-bin/tmp/${EXECUTABLE}.zsh: bin/tmp/${EXECUTABLE}
-	bin/tmp/${EXECUTABLE} completion zsh > ${@}
+${EXECUTABLE}.zsh: ${EXECUTABLE}
+	${EXECUTABLE} completion zsh > ${@}
 
 # UN/INSTALL
 # ==============================================================================
 PHONY+=install
-install: bin/tmp/${EXECUTABLE} bin/tmp/${EXECUTABLE}.sh bin/tmp/${EXECUTABLE}.fish bin/tmp/${EXECUTABLE}.zsh
+install: ${EXECUTABLE} ${EXECUTABLE}.sh ${EXECUTABLE}.fish ${EXECUTABLE}.zsh
 	install --directory ${DESTDIR}${PREFIX}/bin
-	install --mode 755 bin/tmp/${EXECUTABLE} ${DESTDIR}${PREFIX}/bin/${EXECUTABLE}
-
-	install --directory ${DESTDIR}/etc/bash_completion.d
-	install --mode 755 bin/tmp/${EXECUTABLE}.sh ${DESTDIR}/etc/bash_completion.d/${EXECUTABLE}.sh
-
-	install --directory ${DESTDIR}/usr/share/fish/vendor_completions.d
-	install --mode 644 bin/tmp/${EXECUTABLE}.fish ${DESTDIR}/usr/share/fish/vendor_completions.d/${EXECUTABLE}.fish
+	install --mode 755 ${EXECUTABLE} ${DESTDIR}${PREFIX}/bin/${EXECUTABLE}
 
 	install --directory ${DESTDIR}/usr/lib/systemd/system
 	install --mode 644 systemd/${EXECUTABLE}.service ${DESTDIR}/usr/lib/systemd/system/${EXECUTABLE}.service
 
-	install --directory ${DESTDIR}/usr/share/licenses/${EXECUTABLE}
-	install --mode 644 LICENSE ${DESTDIR}/usr/share/licenses/${EXECUTABLE}/LICENSE
+	install --directory ${DESTDIR}${PREFIX}/share/bash-completion/completions/
+	install --mode 644 ${EXECUTABLE}.sh ${DESTDIR}${PREFIX}/share/bash-completion/completions/${EXECUTABLE}.sh
+
+	install --directory ${DESTDIR}${PREFIX}/fish/vendor_completions.d
+	install --mode 644 ${EXECUTABLE}.fish ${DESTDIR}${PREFIX}/fish/vendor_completions.d/${EXECUTABLE}.fish
+
+	install --directory ${DESTDIR}${PREFIX}/licenses/${EXECUTABLE}
+	install --mode 644 LICENSE ${DESTDIR}${PREFIX}/licenses/${EXECUTABLE}/LICENSE
 
 PHONY+=uninstall
 uninstall:
 	-rm --recursive --force \
 		${DESTDIR}${PREFIX}/bin/${EXECUTABLE} \
-		${DESTDIR}/etc/bash_completion.d/${EXECUTABLE}.sh \
 		${DESTDIR}/usr/lib/systemd/system/${EXECUTABLE}.service \
-		${DESTDIR}/usr/share/fish/vendor_completions.d/${EXECUTABLE}.fish \
-		${DESTDIR}/usr/share/licenses/${EXECUTABLE}/LICENSE
+		${DESTDIR}${PREFIX}/share/bash-completion/completions/${EXECUTABLE}.sh \
+		${DESTDIR}${PREFIX}/fish/vendor_completions.d/${EXECUTABLE}.fish \
+		${DESTDIR}${PREFIX}/licenses/${EXECUTABLE}/LICENSE
 
 # CLEAN
 # ==============================================================================
 PHONY+=clean
 clean:
-	rm --force --recursive bin/ || true
+	rm --force --recursive ${EXECUTABLE}* || true
 
 # TEST
 # ==============================================================================

go.mod

@@ -11,9 +11,9 @@ require (
 	github.com/d2r2/go-logger v0.0.0-20181221090742-9998a510495e
 	github.com/golang-migrate/migrate/v4 v4.14.2-0.20201125065321-a53e6fc42574
 	github.com/johejo/golang-migrate-extra v0.0.0-20210217013041-51a992e50d16
-	github.com/lib/pq v1.9.0
+	github.com/lib/pq v1.10.2
 	github.com/mattn/go-sqlite3 v2.0.3+incompatible
 	github.com/satori/go.uuid v1.2.0
-	github.com/spf13/cobra v1.1.1
+	github.com/spf13/cobra v1.1.3
 	github.com/stretchr/testify v1.7.0
 )

go.sum

@@ -297,6 +297,8 @@ github.com/lib/pq v1.2.0/go.mod h1:5WUZQaWbwv1U+lTReE5YruASi9Al49XbQIvNi/34Woo=
 github.com/lib/pq v1.8.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/lib/pq v1.9.0 h1:L8nSXQQzAYByakOFMTwpjRoHsMJklur4Gi59b6VivR8=
 github.com/lib/pq v1.9.0/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
+github.com/lib/pq v1.10.2 h1:AqzbZs4ZoCBp+GtejcpCpcxM3zlSMx29dXbUSeVtJb8=
+github.com/lib/pq v1.10.2/go.mod h1:AlVN5x4E4T544tWzH6hKfbfQvm3HdbOxrmggDNAPY9o=
 github.com/magiconair/properties v1.8.1/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/markbates/pkger v0.15.1/go.mod h1:0JoVlrol20BSywW79rN3kdFFsE5xYM+rSCQDXbLhiuI=
 github.com/mattn/go-colorable v0.0.9/go.mod h1:9vuHe8Xs5qXnSaW/c/ABM9alt+Vo+STaOChaDxuIBZU=
@@ -388,6 +390,8 @@ github.com/spf13/afero v1.1.2/go.mod h1:j4pytiNVoe2o6bmDsKpLACNPDBIoEAkihy7loJ1B
 github.com/spf13/cast v1.3.0/go.mod h1:Qx5cxh0v+4UWYiBimWS+eyWzqEqokIECu5etghLkUJE=
 github.com/spf13/cobra v1.1.1 h1:KfztREH0tPxJJ+geloSLaAkaPkr4ki2Er5quFV1TDo4=
 github.com/spf13/cobra v1.1.1/go.mod h1:WnodtKOvamDL/PwE2M4iKs8aMDBZ5Q5klgD3qfVJQMI=
+github.com/spf13/cobra v1.1.3 h1:xghbfqPkxzxP3C/f3n5DdpAbdKLj4ZE4BWQI362l53M=
+github.com/spf13/cobra v1.1.3/go.mod h1:pGADOWyqRD/YMrPZigI/zbliZ2wVD/23d+is3pSWzOo=
 github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb68N+wFjFa4jdeBTo=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
@@ -395,6 +399,7 @@ github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An
 github.com/spf13/viper v1.7.0/go.mod h1:8WkrPz2fc9jxqZNCJI/76HCieCp4Q8HaLFoCha5qpdg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/objx v0.2.0 h1:Hbg2NidpLE8veEBkEZTL3CvlkUIVzuU9jDplZO54c48=
 github.com/stretchr/objx v0.2.0/go.mod h1:qt09Ya8vawLte6SNmTgCsAVtYtaKzEcn8ATUoHMkEqE=
 github.com/stretchr/testify v1.2.0/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
@@ -745,6 +750,7 @@ gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.4/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.7/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo=
 gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gotest.tools v2.2.0+incompatible h1:VsBPFP1AI068pPrMxtb/S8Zkgf9xEmTLJjfM+P5UIEo=

pkg/repository/postgres/ddl/8_table_measured_values.down.sql

@@ -0,0 +1,95 @@
+-- Remove constraints to table measured_values
+ALTER TABLE humidities
+DROP CONSTRAINT fk_humidites_measured_value_id;
+
+ALTER TABLE pressures
+DROP CONSTRAINT fk_pressures_measured_value_id;
+
+ALTER TABLE temperatures
+DROP CONSTRAINT fk_temperatures_measured_value_id;
+
+-- Rename measured_value_id to sensor_id
+ALTER TABLE humidities
+RENAME COLUMN measured_value_id TO sensor_id;
+
+ALTER TABLE pressures
+RENAME COLUMN measured_value_id TO sensor_id;
+
+ALTER TABLE temperatures
+RENAME COLUMN measured_value_id TO sensor_id;
+
+-- Add new column measures_value_id with data from sensor_id
+ALTER TABLE humidities
+ADD COLUMN measured_value_id CHAR(36);
+
+UPDATE humidities
+SET measured_value_id=sensor_id;
+
+ALTER TABLE pressures
+ADD COLUMN measured_value_id CHAR(36);
+
+UPDATE pressures
+SET measured_value_id=sensor_id;
+
+ALTER TABLE temperatures
+ADD COLUMN measured_value_id CHAR(36);
+
+UPDATE temperatures
+SET measured_value_id=sensor_id;
+
+-- Update sensor_id's
+UPDATE humidities h
+SET sensor_id = (
+  SELECT m.sensor_id
+  FROM measured_values m
+  WHERE m.id = h.measured_value_id
+);
+
+UPDATE pressures p
+SET sensor_id = (
+  SELECT m.sensor_id
+  FROM measured_values m
+  WHERE m.id = p.measured_value_id
+);
+
+UPDATE temperatures t
+SET sensor_id = (
+  SELECT m.sensor_id
+  FROM measured_values m
+  WHERE m.id = t.measured_value_id
+);
+
+-- Delete sensor_id columns
+ALTER TABLE humidities
+DROP COLUMN measured_value_id;
+
+ALTER TABLE pressures
+DROP COLUMN measured_value_id;
+
+ALTER TABLE temperatures
+DROP COLUMN measured_value_id;
+
+-- Add foreign keys
+ALTER TABLE humidities
+ADD CONSTRAINT fk_humidites_sensor_id
+FOREIGN KEY (sensor_id)
+REFERENCES sensors(sensor_id)
+ON DELETE CASCADE
+ON UPDATE CASCADE;
+
+ALTER TABLE pressures
+ADD CONSTRAINT fk_pressures_sensor_id
+FOREIGN KEY (sensor_id)
+REFERENCES sensors(sensor_id)
+ON DELETE CASCADE
+ON UPDATE CASCADE;
+
+ALTER TABLE temperatures
+ADD CONSTRAINT fk_temperatures_sensor_id
+FOREIGN KEY (sensor_id)
+REFERENCES sensors(sensor_id)
+ON DELETE CASCADE
+ON UPDATE CASCADE;
+
+-- drop measured values table
+DROP TABLE measured_values CASCADE;

pkg/repository/postgres/ddl/8_table_measured_values.up.sql

@@ -0,0 +1,130 @@
+-- Create measures_values table.
+-- This table represent a collection of different measured values, because it
+-- can be possible, that a sensor returns multiple measured values. For example
+-- the BME280 semsor returns humidity, pressure and temperature values.
+CREATE TABLE measured_values (
+  id                      CHAR(36)                                                NOT NULL,
+  sensor_id               CHAR(36)                                                NOT NULL,
+  creation_date           TIMESTAMP WITH TIME ZONE    DEFAULT CURRENT_TIMESTAMP   NOT NULL,
+  update_date             TIMESTAMP WITH TIME ZONE,
+  CONSTRAINT pk_measured_value PRIMARY KEY(id),
+  CONSTRAINT pk_measured_value_sensor_id FOREIGN KEY(sensor_id) REFERENCES sensors(sensor_id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- Remove constraints to table sensor
+ALTER TABLE humidities
+DROP CONSTRAINT fk_humidites_sensor_id;
+
+ALTER TABLE pressures
+DROP CONSTRAINT fk_pressures_sensor_id;
+
+ALTER TABLE temperatures
+DROP CONSTRAINT fk_temperatures_sensor_id;
+
+-- Rename sensor_id to measured_value_id
+ALTER TABLE humidities
+RENAME COLUMN sensor_id TO measured_value_id;
+
+ALTER TABLE pressures
+RENAME COLUMN sensor_id TO measured_value_id;
+
+ALTER TABLE temperatures
+RENAME COLUMN sensor_id TO measured_value_id;
+
+-- Add new column sensor_id with data from measures_value_id
+ALTER TABLE humidities
+ADD COLUMN sensor_id CHAR(36);
+
+UPDATE humidities
+SET sensor_id=measured_value_id;
+
+ALTER TABLE pressures
+ADD COLUMN sensor_id CHAR(36);
+
+UPDATE pressures
+SET sensor_id=measured_value_id;
+
+ALTER TABLE temperatures
+ADD COLUMN sensor_id CHAR(36);
+
+UPDATE temperatures
+SET sensor_id=measured_value_id;
+
+
+DO $$
+DECLARE
+  f record;
+BEGIN
+  FOR f IN (
+    SELECT
+      md5(random()::text || clock_timestamp()::text)::uuid AS measured_value_id,
+      h.id AS humidity_id,
+      p.id AS pressure_id,
+      t.id AS temperature_id,
+      CASE WHEN h.sensor_id IS NOT NULL THEN h.sensor_id
+           WHEN p.sensor_id IS NOT NULL THEN p.sensor_id
+           WHEN t.sensor_id IS NOT NULL THEN t.sensor_id
+           ELSE NULL
+      END sensor_id
+    FROM pressures p
+      FULL OUTER JOIN temperatures t ON (t.date = p.date AND t.sensor_id = p.sensor_id)
+      FULL OUTER JOIN humidities h ON (h.date = p.date AND h.sensor_id = p.sensor_id)
+  ) LOOP
+
+    -- MEASURED_VALUE
+    INSERT INTO measured_values(id, sensor_id, creation_date, update_date)
+    VALUES (f.measured_value_id, f.sensor_id, NOW(), NULL)
+    ON CONFLICT (
+      id
+    )
+    DO NOTHING;
+
+    -- HUMIDITY
+    UPDATE humidities
+    SET measured_value_id=f.measured_value_id
+    WHERE id=f.humidity_id;
+
+    -- PRESSURE
+    UPDATE pressures
+    SET measured_value_id=f.measured_value_id
+    WHERE id=f.pressure_id;
+
+    -- TEMPERATURES
+    UPDATE temperatures
+    SET measured_value_id=f.measured_value_id
+    WHERE id=f.temperature_id;
+  END LOOP;
+END;
+$$;
+
+-- Delete sensor_id columns
+ALTER TABLE humidities
+DROP COLUMN sensor_id;
+
+ALTER TABLE pressures
+DROP COLUMN sensor_id;
+
+ALTER TABLE temperatures
+DROP COLUMN sensor_id;
+
+-- Add foreign keys
+ALTER TABLE humidities
+ADD CONSTRAINT fk_humidites_measured_value_id
+FOREIGN KEY (measured_value_id)
+REFERENCES measured_values(id)
+ON DELETE CASCADE
+ON UPDATE CASCADE;
+
+ALTER TABLE pressures
+ADD CONSTRAINT fk_pressures_measured_value_id
+FOREIGN KEY (measured_value_id)
+REFERENCES measured_values(id)
+ON DELETE CASCADE
+ON UPDATE CASCADE;
+
+ALTER TABLE temperatures
+ADD CONSTRAINT fk_temperatures_measured_value_id
+FOREIGN KEY (measured_value_id)
+REFERENCES measured_values(id)
+ON DELETE CASCADE
+ON UPDATE CASCADE;

pkg/repository/sqlite3/ddl/6_table_measured_values.down.sql

@@ -0,0 +1,90 @@
+-- All tables with the original data rows must be renamed, because it is not
+-- possible to remove existing foreign keys. The tables will be recreated with
+-- a new column measured_value_id which reference on the primary key of the
+-- table measured values.
+--
+-- More about why it is not possible to delete a foreign key is described here:
+-- https://stackoverflow.com/a/1884893/7652996
+ALTER TABLE humidities
+RENAME TO humidities_backup;
+
+CREATE TABLE humidities (
+  id                      CHAR(36)                                                  NOT NULL,
+  value                   NUMERIC(10,3)                                             NOT NULL,
+  date                    TIMESTAMP                                                 NOT NULL,
+  sensor_id               CHAR(36)                                                  NOT NULL,
+  creation_date           TIMESTAMP       DEFAULT (datetime('now', 'localtime'))    NOT NULL,
+  update_date             TIMESTAMP,
+  CONSTRAINT pk_humidities PRIMARY KEY(id),
+  CONSTRAINT fk_humidities_sensor_id FOREIGN KEY(sensor_id) REFERENCES sensors(sensor_id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+ALTER TABLE pressures
+RENAME TO pressures_backup;
+
+CREATE TABLE pressures (
+  id                      CHAR(36)                                                  NOT NULL,
+  value                   NUMERIC(10,3)                                             NOT NULL,
+  date                    TIMESTAMP                                                 NOT NULL,
+  sensor_id               CHAR(36)                                                  NOT NULL,
+  creation_date           TIMESTAMP       DEFAULT (datetime('now', 'localtime'))    NOT NULL,
+  update_date             TIMESTAMP,
+  CONSTRAINT pk_pressures PRIMARY KEY(id),
+  CONSTRAINT fk_pressures_sensor_id FOREIGN KEY(sensor_id) REFERENCES sensors(sensor_id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+ALTER TABLE temperatures
+RENAME TO temperatures_backup;
+
+CREATE TABLE temperatures (
+  id                      CHAR(36)                                                  NOT NULL,
+  value                   NUMERIC(10,3)                                             NOT NULL,
+  date                    TIMESTAMP                                                 NOT NULL,
+  sensor_id               CHAR(36)                                                  NOT NULL,
+  creation_date           TIMESTAMP       DEFAULT (datetime('now', 'localtime'))    NOT NULL,
+  update_date             TIMESTAMP,
+  CONSTRAINT pk_temperatures PRIMARY KEY(id),
+  CONSTRAINT fk_temperatures_id FOREIGN KEY(sensor_id) REFERENCES sensors(sensor_id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- Filling tables humidities, pressures and temperatures with the data from the
+-- backup table.
+INSERT INTO humidities
+SELECT
+  h.id,
+  h.value,
+  h.date,
+  m.sensor_id,
+  h.creation_date,
+  h.update_date
+FROM humidities_backup h
+  INNER JOIN measured_values m ON (m.id = h.measured_value_id);
+
+INSERT INTO pressures
+SELECT
+  p.id,
+  p.value,
+  p.date,
+  m.sensor_id,
+  p.creation_date,
+  p.update_date
+FROM pressures_backup p
+  INNER JOIN measured_values m ON (m.id = p.measured_value_id);
+
+INSERT INTO temperatures
+SELECT
+  t.id,
+  t.value,
+  t.date,
+  m.sensor_id,
+  t.creation_date,
+  t.update_date
+FROM temperatures_backup t
+  INNER JOIN measured_values m ON (m.id = t.measured_value_id);
+
+-- The remaining tables, which were only necessary for the migration,
+-- are now removed.
+DROP TABLE humidities_backup;
+DROP TABLE pressures_backup;
+DROP TABLE temperatures_backup;
+DROP TABLE measured_values;

pkg/repository/sqlite3/ddl/6_table_measured_values.up.sql

@@ -0,0 +1,189 @@
+-- Create measures_values table.
+-- This table represent a collection of different measured values, because it
+-- can be possible, that a sensor returns multiple measured values. For example
+-- the BME280 semsor returns humidity, pressure and temperature values.
+CREATE TABLE measured_values (
+  id                      CHAR(36)                                                NOT NULL,
+  sensor_id               CHAR(36)                                                NOT NULL,
+  creation_date           TIMESTAMP WITH TIME ZONE    DEFAULT CURRENT_TIMESTAMP   NOT NULL,
+  update_date             TIMESTAMP WITH TIME ZONE,
+  CONSTRAINT pk_measured_value PRIMARY KEY(id),
+  CONSTRAINT pk_measured_value_sensor_id FOREIGN KEY(sensor_id) REFERENCES sensors(sensor_id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- All tables with the original data rows must be renamed, because it is not
+-- possible to remove existing foreign keys. The tables will be recreated with
+-- a new column measured_value_id which reference on the primary key of the
+-- table measured values.
+--
+-- More about why it is not possible to delete a foreign key is described here:
+-- https://stackoverflow.com/a/1884893/7652996
+ALTER TABLE humidities
+RENAME TO humidities_backup;
+
+CREATE TABLE humidities (
+  id                      CHAR(36)                                                  NOT NULL,
+  value                   NUMERIC(10,3)                                             NOT NULL,
+  date                    TIMESTAMP                                                 NOT NULL,
+  measured_value_id       CHAR(36)                                                  NOT NULL,
+  creation_date           TIMESTAMP       DEFAULT (datetime('now', 'localtime'))    NOT NULL,
+  update_date             TIMESTAMP,
+  CONSTRAINT pk_humidities PRIMARY KEY(id),
+  CONSTRAINT fk_humidities_measured_value_id FOREIGN KEY(measured_value_id) REFERENCES measured_values(id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+ALTER TABLE pressures
+RENAME TO pressures_backup;
+
+CREATE TABLE pressures (
+  id                      CHAR(36)                                                  NOT NULL,
+  value                   NUMERIC(10,3)                                             NOT NULL,
+  date                    TIMESTAMP                                                 NOT NULL,
+  measured_value_id       CHAR(36)                                                  NOT NULL,
+  creation_date           TIMESTAMP       DEFAULT (datetime('now', 'localtime'))    NOT NULL,
+  update_date             TIMESTAMP,
+  CONSTRAINT pk_pressures PRIMARY KEY(id),
+  CONSTRAINT fk_pressures_measured_value_id FOREIGN KEY(measured_value_id) REFERENCES measured_values(id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+ALTER TABLE temperatures
+RENAME TO temperatures_backup;
+
+CREATE TABLE temperatures (
+  id                      CHAR(36)                                                  NOT NULL,
+  value                   NUMERIC(10,3)                                             NOT NULL,
+  date                    TIMESTAMP                                                 NOT NULL,
+  measured_value_id       CHAR(36)                                                  NOT NULL,
+  creation_date           TIMESTAMP       DEFAULT (datetime('now', 'localtime'))    NOT NULL,
+  update_date             TIMESTAMP,
+  CONSTRAINT pk_temperatures PRIMARY KEY(id),
+  CONSTRAINT fk_temperatures_measured_value_id FOREIGN KEY(measured_value_id) REFERENCES measured_values(id) ON DELETE CASCADE ON UPDATE CASCADE
+);
+
+-- The following two views are necessary to create a FULL OUTER JOIN via the
+-- tables humidities, pressures and temperatures, as this is not supported in
+-- SQLite. More about this here:
+--
+-- https://stackoverflow.com/questions/12759087/full-outer-join-in-sqlite-on-4-tables
+CREATE VIEW humidities_pressures AS
+SELECT
+  h.id AS humidity_id,
+  h.value AS humidity_value,
+  h.date AS humidity_date,
+  h.sensor_id AS humidity_sensor_id,
+  h.creation_date AS humidity_creation_date,
+  h.update_date AS humidity_update_date,
+  p.id AS pressure_id,
+  p.value AS pressure_value,
+  p.date AS pressure_date,
+  p.sensor_id AS pressure_sensor_id,
+  p.creation_date AS pressure_creation_date,
+  p.update_date AS pressure_update_date
+FROM humidities_backup h
+  LEFT JOIN pressures_backup p ON (h.date = p.date AND h.sensor_id = p.sensor_id)
+UNION ALL
+SELECT
+  h.id AS humidity_id,
+  h.value AS humidity_value,
+  h.date AS humidity_date,
+  h.sensor_id AS humidity_sensor_id,
+  h.creation_date AS humidity_creation_date,
+  h.update_date AS humidity_update_date,
+  p.id AS pressure_id,
+  p.value AS pressure_value,
+  p.date AS pressure_date,
+  p.sensor_id AS pressure_sensor_id,
+  p.creation_date AS pressure_creation_date,
+  p.update_date AS pressure_update_date
+FROM pressures_backup p
+  LEFT JOIN humidities_backup h ON (p.date = h.date AND p.sensor_id = h.sensor_id)
+WHERE h.date IS NULL
+AND h.sensor_id IS NULL;
+
+CREATE VIEW joined_values AS
+SELECT
+  hp.*,
+  t.id AS temperature_id,
+  t.value AS temperature_value,
+  t.date AS temperature_date,
+  t.sensor_id AS temperature_sensor_id,
+  t.creation_date AS temperature_creation_date,
+  t.update_date AS temperature_update_date
+FROM temperatures_backup t
+  LEFT JOIN humidities_pressures hp ON (t.date = hp.pressure_date AND t.sensor_id = hp.pressure_sensor_id)
+UNION ALL
+SELECT
+  hp.*,
+  t.id AS temperature_id,
+  t.value AS temperature_value,
+  t.date AS temperature_date,
+  t.sensor_id AS temperature_sensor_id,
+  t.creation_date AS temperature_creation_date,
+  t.update_date AS temperature_update_date
+FROM humidities_pressures hp
+  LEFT JOIN temperatures_backup t ON (t.date = hp.pressure_date  AND t.sensor_id = hp.pressure_sensor_id)
+WHERE t.date IS NULL
+AND t.sensor_id IS NULL;
+
+-- The date and the SensorID are used as primary key between the tables
+-- humidities, pressures and temperatures. Based on this information, a
+-- MeasuredValueID is generated. The data records are then inserted into the
+-- table.
+INSERT INTO measured_values (id, creation_date, sensor_id)
+SELECT
+  LOWER(HEX(RANDOMBLOB(4)) || '-' || HEX(RANDOMBLOB(2)) || '-' || '4' || SUBSTR(HEX(RANDOMBLOB(2)), 2) || '-' || SUBSTR('AB89', 1 + (ABS(random()) % 4) , 1) || SUBSTR(HEX(RANDOMBLOB(2)), 2) || '-' || HEX(RANDOMBLOB(6))) AS measured_value_id,
+  CASE WHEN humidity_date IS NOT NULL THEN humidity_date
+    WHEN pressure_date IS NOT NULL THEN pressure_date
+    WHEN temperature_date IS NOT NULL THEN temperature_date
+    ELSE NULL
+  END date,
+	CASE WHEN humidity_sensor_id IS NOT NULL THEN humidity_sensor_id
+      WHEN pressure_sensor_id IS NOT NULL THEN pressure_sensor_id
+      WHEN temperature_sensor_id IS NOT NULL THEN temperature_sensor_id
+      ELSE NULL
+  END sensor_id
+FROM joined_values;
+
+-- In the following, the original data records from the backup are restored with
+-- the difference that the MeasuredValueID is added as a foreign key based on
+-- the date and the SensorID.
+INSERT INTO humidities (id, value, date, measured_value_id, creation_date, update_date)
+SELECT
+	jv.humidity_id,
+	jv.humidity_value,
+	jv.humidity_date,
+	(SELECT mv.id FROM measured_values mv WHERE mv.creation_date = jv.humidity_date AND mv.sensor_id = jv.humidity_sensor_id) AS measured_value,
+  jv.humidity_creation_date,
+  jv.humidity_update_date
+FROM joined_values jv
+WHERE humidity_id IS NOT NULL;
+
+INSERT INTO pressures (id, value, date, measured_value_id, creation_date, update_date)
+SELECT
+	jv.pressure_id,
+	jv.pressure_value,
+	jv.pressure_date,
+	(SELECT mv.id FROM measured_values mv WHERE mv.creation_date = jv.pressure_date AND mv.sensor_id = jv.pressure_sensor_id) AS measured_value,
+  jv.pressure_creation_date,
+  jv.pressure_update_date
+FROM joined_values jv
+WHERE pressure_id IS NOT NULL;
+
+INSERT INTO temperatures (id, value, date, measured_value_id, creation_date, update_date)
+SELECT
+	jv.temperature_id,
+	jv.temperature_value,
+	jv.temperature_date,
+	(SELECT mv.id FROM measured_values mv WHERE mv.creation_date = jv.temperature_date AND mv.sensor_id = jv.temperature_sensor_id) AS measured_value,
+  jv.temperature_creation_date,
+  jv.temperature_update_date
+FROM joined_values jv
+WHERE temperature_id IS NOT NULL;
+
+-- The remaining views and tables, which were only necessary for the migration,
+-- are now removed.
+DROP VIEW humidities_pressures;
+DROP VIEW joined_values;
+DROP TABLE humidities_backup;
+DROP TABLE pressures_backup;
+DROP TABLE temperatures_backup;