How to export (dump) WebSQL data - json

Question

I'm working on a Chrome Extension that uses WebSQL to store historical data.
Being WebSQL, the DB is stored on the client.
I'd like to add an option to export/import such data so that the user can share/use this data with other users, or with other PCs.
These are my first steps on a client-only database, so I wonder how to do this.
I was thinking to convert the DB to a huge json string that the user can copy/paste but doesn't look very user-friendly.
Is there any better solution?

Answer 1

I got a single table dump solution working on a HTML5 database client I wrote a few days ago.
Check out http://html5db.desalasworks.com/script.js and scroll down to SqlClient.exportTable, this has an example that needs to be expanded to cover the whole database.
The steps are:
Step 1: Create the schema:
SELECT sql FROM sqlite_master
Step 2: Get a list of tables:
SELECT tbl_name from sqlite_master WHERE type = 'table'
Step 3: Loop through each of them and create an INSERT script with the results
transaction.executeSql("SELECT * FROM " + _tbl_name + ";", [],
function(transaction, results) {
if (results.rows) {
for (var i = 0; i < results.rows.length; i++) {
var row = results.rows.item(i);
var _fields = [];
var _values = [];
for (col in row) {
_fields.push(col);
_values.push('"' + row[col] + '"');
}
_exportSql += ";\nINSERT INTO " + _tbl_name + "(" + _fields.join(",") + ") VALUES (" + _values.join(",") + ")";
}
}
}
);
Hope this is useful.
UPDATE JAN 2016 - WHOLE DB EXPORT
I've got a JS websqldump library that you can download from github as well.
This one will export the whole database. Check out the code on:
https://github.com/sdesalas/websqldump
Usage as follows
websqldump.export({
database: 'NorthwindLite',
success: function(sql) {alert(sql);}
});

Answer 2

Not the most elegant way, yet most convenient.
Just paste the script in chrome debugger tools then call c(), and you should get the file.
var looongSQL = "";
var x = function (options) {
if (options.n < options.sqlTables.length) {
onTheMove.openLocalDatabase().transaction(
function (tx) {
var sqlStatement = "SELECT * FROM " + options.sqlTables[options.n];
tx.executeSql(sqlStatement, [],
function (tx, rslt) {
if (rslt.rows) {
for (var m = 0; m < rslt.rows.length; m++) {
var dataRow = rslt.rows.item(m);
var _fields = [];
var _values = [];
for (col in dataRow) {
_fields.push(col);
_values.push('"' + dataRow[col] + '"');
}
looongSQL += "INSERT INTO " + options.sqlTables[options.n] + "(" + _fields.join(",") + ") VALUES (" + _values.join(",") + ");\n";
}
}
options.n++;
x(options);
}
);
});
}else
{
document.location = 'data:Application/octet-stream,' +
encodeURIComponent(looongSQL);
}
};
var c = function () {
onTheMove.openLocalDatabase().transaction(
function (transaction) {
transaction.executeSql("SELECT sql FROM sqlite_master;", [],
function (transaction, results) {
var sqlStatements = [];
if (results.rows) {
for (var i = 0; i < results.rows.length; i++) {
console.log(results.rows.item(i));
var row = results.rows.item(i);
if (row.sql != null && row.sql.indexOf("CREATE TABLE ") != -1 && row.sql.indexOf("__") == -1) {
var tableName = row.sql.replace("CREATE TABLE ", "").split(/ |\(/)[0];
sqlStatements.push('DROP TABLE IF EXISTS ' + tableName);
}if(row.sql != null && row.sql.indexOf("__") == -1){
sqlStatements.push(row.sql);}
}
}
for (var j = 0; j < sqlStatements.length; j++) {
if (sqlStatements[j] != null) {
looongSQL += sqlStatements[j] + ';\r\n';
}
}
transaction.executeSql("SELECT tbl_name from sqlite_master WHERE type = 'table'", [],
function (transaction, res) {
var sqlTables = [];
for (var k = 0; k < res.rows.length; k++) {
if (res.rows.item(k).tbl_name.indexOf("__") == -1) {
sqlTables.push(res.rows.item(k).tbl_name);
}
}
x({
sqlTables: sqlTables,
n: 0
});
});
}
);
});
};
Another version that exports it as JSON
var looongSQL = "[\n";
var stringidiedLocalStorage = JSON.stringify(JSON.stringify(localStorage));
looongSQL += "/* 1 */ " + stringidiedLocalStorage + ",\n";
var x = function (options) {
if (options.n < options.sqlTables.length) {
onTheMove.openLocalDatabase().transaction(
function (tx) {
var sqlStatement = "SELECT * FROM " + options.sqlTables[options.n];
tx.executeSql(sqlStatement, [],
function (tx, rslt) {
if (rslt.rows && rslt.rows.length > 0) {
var _fields = [];
for (var col in rslt.rows.item(0)) {
_fields.push(col);
}
var insertTableSQL = "\"INSERT INTO " + options.sqlTables[options.n] + "(" + _fields.join(",") + ") ";
looongSQL += "/* " + options.count + " */ " + insertTableSQL;
for (var m = 0; m < rslt.rows.length; m++) {
var dataRow = rslt.rows.item(m);
var _values = [];
for (var col in dataRow) {
_values.push('\'' + dataRow[col] + '\'');
}
looongSQL += "SELECT " + _values.join(",");
if (m < rslt.rows.length - 1 && (m % 499 != 0 || m == 0)) {
looongSQL += " UNION ALL ";
}
if (m % 499 == 0 && m != 0) {
options.count++;
looongSQL += "\",\r\n/* " + options.count + " */ " + insertTableSQL;
}
}
looongSQL += "\",\r\n";
options.count++;
}
options.n++;
x(options);
}
);
});
} else {
looongSQL += ']';
document.location = 'data:Application/octet-stream,' +
encodeURIComponent(looongSQL);
}
};
var c = function () {
onTheMove.openLocalDatabase().transaction(
function (transaction) {
transaction.executeSql("SELECT sql FROM sqlite_master;", [],
function (transaction, results) {
var sqlStatements = [];
var count = 2;
if (results.rows) {
for (var i = 0; i < results.rows.length; i++) {
console.log(results.rows.item(i));
var row = results.rows.item(i);
if (row.sql != null && row.sql.indexOf("CREATE ") != -1) {
var objectType = row.sql.replace("CREATE ", "").split(/ |\(/)[0];
if (row.sql.indexOf("CREATE " + objectType + " ") != -1 && row.sql.indexOf("__") == -1) {
var objectName = row.sql.replace("CREATE " + objectType + " ", "").split(/ |\(/)[0];
sqlStatements.push('/* ' + count + ' */ "DROP ' + objectType + ' IF EXISTS ' + objectName + '"');
count++;
}
if (row.sql != null && row.sql.indexOf("__") == -1) {
sqlStatements.push('/* ' + count + ' */ "' + row.sql.replace(/(\r\n|\n|\r)/gm, " ") + '"');
count++;
}
}
}
}
for (var j = 0; j < sqlStatements.length; j++) {
if (sqlStatements[j] != null) {
looongSQL += sqlStatements[j] + ',\r\n';
}
}
transaction.executeSql("SELECT tbl_name from sqlite_master WHERE type = 'table'", [],
function (transaction, res) {
var sqlTables = [];
for (var k = 0; k < res.rows.length; k++) {
if (res.rows.item(k).tbl_name.indexOf("__") == -1) {
sqlTables.push(res.rows.item(k).tbl_name);
}
}
x({
sqlTables: sqlTables,
n: 0,
count: count
});
});
}
);
});
};