Doc: added support for JSON in localstorage documentation

Added examples on how to store in JSON format

Change-Id: Ief58e28d42cd87cc0829e9265670e7c7bbdbeffe
Reviewed-by: Mitch Curtis <mitch.curtis@qt.io>

2 files changed, 41 insertions, 11 deletions

diff --git a/src/imports/localstorage/plugin.cpp b/src/imports/localstorage/plugin.cpp
index cd6d37ea5a..6704283cb9 100644
--- a/src/imports/localstorage/plugin.cpp
+++ b/src/imports/localstorage/plugin.cpp
@@ -640,14 +640,32 @@ Below you will find an example of a database transaction which catches exception
 
 \snippet qml/localstorage/dbtransaction.js 0
 
+In the example you can see an \c insert statement where values are assigned to the fields,
+and the record is written into the table. That is an \c insert statement with a syntax that is usual
+for a relational database. It is however also possible to work with JSON objects and
+store them in a table.
+
+Let's suppose a simple example where we store trips in JSON format using \c date as the unique key.
+An example of a table that could be used for that purpose:
+
+\snippet qml/localstorage/dbtransaction.js 3
+
+The assignment of values to a JSON object:
+
+\snippet qml/localstorage/dbtransaction.js 4
+
+In that case, the data could be saved in the following way:
+
+\snippet qml/localstorage/dbtransaction.js 5
+
 \section3 db.readTransaction(callback(tx))
 
 This method creates a read-only transaction and passed to \e callback. In this function,
-you can call \e executeSql on \e tx to read the database (with SELECT statements).
+you can call \e executeSql on \e tx to read the database (with \c select statements).
 
 \section3 results = tx.executeSql(statement, values)
 
-This method executes a SQL \e statement, binding the list of \e values to SQL positional parameters ("?").
+This method executes an SQL \e statement, binding the list of \e values to SQL positional parameters ("?").
 
 It returns a results object, with the following properties:
 
diff --git a/src/quick/doc/snippets/qml/localstorage/dbtransaction.js b/src/quick/doc/snippets/qml/localstorage/dbtransaction.js
index 40eb6d2804..38733a8e2c 100644
--- a/src/quick/doc/snippets/qml/localstorage/dbtransaction.js
+++ b/src/quick/doc/snippets/qml/localstorage/dbtransaction.js
@@ -43,11 +43,11 @@ var db = LocalStorage.openDatabaseSync("ActivityTrackDB", "", "Database tracking
 db.transaction(
     try {
         function(tx) {
-            tx.executeSql('INSERT INTO trip_log VALUES(?, ?, ?)',
-                          [ '01/10/2016','Sylling - Vikersund', '53' ]);
+            tx.executeSql("INSERT INTO trip_log VALUES(?, ?, ?)",
+                          [ "01/10/2016","Sylling - Vikersund", "53" ]);
         }
     }   catch (err) {
-            console.log("Error inserting into table Greeting: " + err);
+            console.log("Error inserting into table trip_log: " + err);
         }
 )
 //![0]
@@ -60,11 +60,11 @@ function db_distance_select(Pdistance)
 var db = LocalStorage.openDatabaseSync("ActivityTrackDB", "", "Database tracking sports activities", 1000000);
 db.transaction(
     function(tx) {
-        var results = tx.executeSql('SELECT rowid,
+        var results = tx.executeSql("SELECT rowid,
                                             date,
                                             trip_desc,
                                             distance FROM trip_log
-                                     where distance >= ?',[Pdistance]');
+                                     where distance >= ?",[Pdistance]);
         for (var i = 0; i < results.rows.length; i++) {
             listModel.append({"id": results.rows.item(i).rowid,
                               "date": results.rows.item(i).date,
@@ -76,10 +76,22 @@ db.transaction(
 //![1]
 //![2]
 var db = LocalStorage.openDatabaseSync("ActivityTrackDB", "", "Database tracking sports activities", 1000000);
-if (db.version == '0.1') {
-    db.changeVersion('0.1', '0.2', function(tx) {
-        tx.executeSql('INSERT INTO trip_log VALUES(?, ?, ?)',
-                    [ '01/10/2016','Sylling - Vikersund', '53' ]);
+if (db.version == "0.1") {
+    db.changeVersion("0.1", "0.2", function(tx) {
+        tx.executeSql("INSERT INTO trip_log VALUES(?, ?, ?)",
+                    [ "01/10/2016","Sylling - Vikersund", "53" ]);
     }
 });
 //![2]
+//![3]
+create table trip_log(date text, data text)
+//![3]
+//![4]
+var obj = {description = "Vikersund - Noresund", distance = "60"}
+//![4]
+//![5]
+db.transaction(function(tx) {
+    result = tx.executeSQL("insert into trip_log values (?,?)",
+                           ["01/11/2016", JSON.stringify(obj)])
+}
+//![5]