MOBILE-2261 core: Implement DB provider

src/app/app.module.ts

@@ -3,9 +3,11 @@ import { ErrorHandler, NgModule } from '@angular/core';
 import { IonicApp, IonicErrorHandler, IonicModule } from 'ionic-angular';
 import { SplashScreen } from '@ionic-native/splash-screen';
 import { StatusBar } from '@ionic-native/status-bar';
+import { SQLite } from '@ionic-native/sqlite';
 
 import { MyApp } from './app.component';
 import { CoreLoggerProvider } from '../providers/logger';
+import { CoreDbProvider } from '../providers/db';
 
 @NgModule({
   declarations: [
@@ -22,8 +24,10 @@ import { CoreLoggerProvider } from '../providers/logger';
   providers: [
     StatusBar,
     SplashScreen,
+    SQLite,
     {provide: ErrorHandler, useClass: IonicErrorHandler},
-    CoreLoggerProvider
+    CoreLoggerProvider,
+    CoreDbProvider
   ]
 })
 export class AppModule {}

src/classes/sqlitedb.ts

@@ -0,0 +1,844 @@
+// (C) Copyright 2015 Martin Dougiamas
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { SQLite, SQLiteObject } from '@ionic-native/sqlite';
+import { Platform } from 'ionic-angular';
+
+/**
+ * Class to interact with the local database.
+ *
+ * @description
+ * This class allows creating and interacting with a SQLite database.
+ *
+ * You need to supply some dependencies when creating the instance:
+ * this.db = new SQLiteDB('MyDB', sqlite, platform);
+ */
+export class SQLiteDB {
+    db: SQLiteObject;
+    promise: Promise<void>;
+
+    /**
+     * Create and open the database.
+     *
+     * @param {string} name Database name.
+     * @param {SQLite} sqlite SQLite library.
+     * @param {Platform} platform Ionic platform.
+     */
+    constructor(public name: string, private sqlite: SQLite, private platform: Platform) {
+        this.init();
+    }
+
+    /**
+     * Helper function to create a table if it doesn't exist.
+     *
+     * @param {string} name The table name.
+     * @param {any[]} columns The columns to create in the table. Each column can have:
+     *                    * {string} name  Column's name.
+     *                    * {string} [type] Column's type.
+     *                    * {boolean} [primaryKey] If column is primary key. Use it only if primary key is a single column.
+     *                    * {boolean} [autoIncrement] Whether it should be autoincremented. Only if primaryKey is true.
+     *                    * {boolean} [notNull] True if column shouldn't be null.
+     *                    * {boolean} [unique] Whether the column is unique.
+     *                    * {string} [check] Check constraint for the column.
+     *                    * {string} [default] Default value for the column.
+     * @param {string[]} [primaryKeys] Names of columns that are primary key. Use it for compound primary keys.
+     * @param {string[][]} [uniqueKeys] List of sets of unique columns. E.g: [['section', 'title'], ['author', 'title']].
+     * @param {any[]} [foreignKeys] List of foreign keys. Each key can have:
+     *                    * {string[]} columns Columns to include in this foreign key.
+     *                    * {string} table The external table referenced by this key.
+     *                    * {string[]} [foreignColumns] List of referenced columns from the referenced table.
+     *                    * {string} [actions] Text with the actions to apply to the foreign key.
+     * @param {string} [tableCheck] Check constraint for the table.
+     * @return SQL query.
+     */
+    buildCreateTableSql(name: string, columns: any[], primaryKeys?: string[], uniqueKeys?: string[][], foreignKeys?: any[],
+                tableCheck?: string) : string {
+        let sql = `CREATE TABLE IF NOT EXISTS ${name} (`,
+            columnsSql = [];
+
+        // First define all the columns.
+        for (let index in columns) {
+            let column = columns[index],
+                columnSql: string = column.name || '';
+
+            if (column.type) {
+                columnSql += ' ' + column.type;
+            }
+
+            if (column.primaryKey) {
+                columnSql += ' PRIMARY KEY';
+                if (column.autoIncrement) {
+                    columnSql += ' AUTOINCREMENT';
+                }
+            }
+
+            if (column.notNull) {
+                columnSql += ' NOT NULL';
+            }
+
+            if (column.unique) {
+                columnSql += ' UNIQUE';
+            }
+
+            if (column.check) {
+                columnSql += ` CHECK (${column.check})`;
+            }
+
+            if (typeof column.default != 'undefined') {
+                columnSql += ` DEFAULT ${column.default}`;
+            }
+
+            columnsSql.push(columnSql);
+        }
+        sql += columnsSql.join(', ') + ')';
+
+        // Now add the table constraints.
+
+        if (primaryKeys && primaryKeys.length) {
+            sql += `, PRIMARY KEY (${primaryKeys.join(', ')})`;
+        }
+
+        if (uniqueKeys && uniqueKeys.length) {
+            for (let index in uniqueKeys) {
+                let setOfKeys = uniqueKeys[index];
+                if (setOfKeys && setOfKeys.length) {
+                    sql += `, UNIQUE (${setOfKeys.join(', ')})`;
+                }
+            }
+        }
+
+        if (tableCheck) {
+            sql += `, CHECK (${tableCheck})`;
+        }
+
+
+        for (let index in foreignKeys) {
+            let foreignKey = foreignKeys[index];
+
+            if (!foreignKey.columns || !!foreignKey.columns.length) {
+                return;
+            }
+
+            sql += `, FOREIGN KEY (${foreignKey.columns.join(', ')}) REFERENCES ${foreignKey.table} `;
+
+            if (foreignKey.foreignColumns && foreignKey.foreignColumns.length) {
+                sql += `(${foreignKey.foreignColumns.join(', ')})`;
+            }
+
+            if (foreignKey.actions) {
+                sql += ` ${foreignKey.actions}`;
+            }
+        }
+
+        return sql;
+    }
+
+    /**
+     * Close the database.
+     */
+    close() {
+        return this.ready().then(() => {
+            return this.db.close();
+        });
+    }
+
+    /**
+     * Count the records in a table where all the given conditions met.
+     *
+     * @param {string} table The table to query.
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @return {Promise<number>} Promise resolved with the count of records returned from the specified criteria.
+     */
+    countRecords(table: string, conditions?: object) : Promise<number> {
+        let selectAndParams = this.whereClause(conditions);
+        return this.countRecordsSelect(table, selectAndParams[0], selectAndParams[1]);
+    }
+
+    /**
+     * Count the records in a table which match a particular WHERE clause.
+     *
+     * @param {string} table The table to query.
+     * @param {string} [select] A fragment of SQL to be used in a where clause in the SQL call.
+     * @param {any} [params] An array of sql parameters.
+     * @param {string} [countItem] The count string to be used in the SQL call. Default is COUNT('x').
+     * @return {Promise<number>} Promise resolved with the count of records returned from the specified criteria.
+     */
+    countRecordsSelect(table: string, select='', params?: any, countItem="COUNT('x')") : Promise<number> {
+        if (select) {
+            select = 'WHERE ' + select;
+        }
+        return this.countRecordsSql(`SELECT ${countItem} FROM ${table} ${select}`, params);
+    }
+
+    /**
+     * Get the result of a SQL SELECT COUNT(...) query.
+     *
+     * Given a query that counts rows, return that count.
+     *
+     * @param {string} sql The SQL string you wish to be executed.
+     * @param {any} [params] An array of sql parameters.
+     * @return {Promise<number>} Promise resolved with the count.
+     */
+    countRecordsSql(sql: string, params?: any) : Promise<number> {
+        return this.getFieldSql(sql, params).then((count) => {
+            if (typeof count != 'number' || count < 0) {
+                return 0;
+            }
+            return count;
+        });
+    }
+
+    /**
+     * Create a table if it doesn't exist.
+     *
+     * @param {string} name The table name.
+     * @param {any[]} columns The columns to create in the table. Each column can have:
+     *                    * {string} name  Column's name.
+     *                    * {string} [type] Column's type.
+     *                    * {boolean} [primaryKey] If column is primary key. Use it only if primary key is a single column.
+     *                    * {boolean} [autoIncrement] Whether it should be autoincremented. Only if primaryKey is true.
+     *                    * {boolean} [notNull] True if column shouldn't be null.
+     *                    * {boolean} [unique] Whether the column is unique.
+     *                    * {string} [check] Check constraint for the column.
+     *                    * {string} [default] Default value for the column.
+     * @param {string[]} [primaryKeys] Names of columns that are primary key. Use it for compound primary keys.
+     * @param {string[][]} [uniqueKeys] List of sets of unique columns. E.g: [['section', 'title'], ['author', 'title']].
+     * @param {any[]} [foreignKeys] List of foreign keys. Each key can have:
+     *                    * {string[]} columns Columns to include in this foreign key.
+     *                    * {string} table The external table referenced by this key.
+     *                    * {string[]} [foreignColumns] List of referenced columns from the referenced table.
+     *                    * {string} [actions] Text with the actions to apply to the foreign key.
+     * @param {string} [tableCheck] Check constraint for the table.
+     * @return {Promise<any>} Promise resolved when success.
+     */
+    createTable(name: string, columns: any[], primaryKeys?: string[], uniqueKeys?: string[][], foreignKeys?: any[],
+                tableCheck?: string) : Promise<any> {
+        let sql = this.buildCreateTableSql(name, columns, primaryKeys, uniqueKeys, foreignKeys, tableCheck);
+        return this.execute(sql);
+    }
+
+    /**
+     * Create a table if it doesn't exist from a schema.
+     *
+     * @param {any} table Table schema.
+     * @return {Promise<any>} Promise resolved when success.
+     */
+    createTableFromSchema(table: any) : Promise<any> {
+        return this.createTable(table.name, table.columns, table.primaryKeys, table.uniqueKeys,
+                table.foreignKeys, table.tableCheck);
+    }
+
+    /**
+     * Create a table if it doesn't exist from a schema.
+     *
+     * @param {any} table Table schema.
+     * @return {Promise<any>} Promise resolved when success.
+     */
+    createTablesFromSchema(tables: any[]) : Promise<any> {
+        let promises = [];
+        tables.forEach((table) => {
+            promises.push(this.createTableFromSchema(table));
+        });
+        return Promise.all(promises);
+    }
+
+    /**
+     * Delete the records from a table where all the given conditions met.
+     * If conditions not specified, table is truncated.
+     *
+     * @param {string} table The table to delete from.
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @return {Promise<any>} Promise resolved when done.
+     */
+    deleteRecords(table: string, conditions?: object) : Promise<any> {
+        if (conditions === null) {
+            // No conditions, delete the whole table.
+            return this.execute(`DELETE FROM TABLE ${table}`);
+        }
+
+        let selectAndParams = this.whereClause(conditions);
+        return this.deleteRecordsSelect(table, selectAndParams[0], selectAndParams[1]);
+    }
+
+    /**
+     * Delete the records from a table where one field match one list of values.
+     *
+     * @param {string} table The table to delete from.
+     * @param {string} field The name of a field.
+     * @param {any[]} values The values field might take.
+     * @return {Promise<any>} Promise resolved when done.
+     */
+    deleteRecordsList(table: string, field: string, values: any[]) : Promise<any> {
+        let selectAndParams = this.whereClauseList(field, values);
+        return this.deleteRecordsSelect(table, selectAndParams[0], selectAndParams[1]);
+    }
+
+    /**
+     * Delete one or more records from a table which match a particular WHERE clause.
+     *
+     * @param {string} table The table to delete from.
+     * @param {string} [select] A fragment of SQL to be used in a where clause in the SQL call.
+     * @param {any[]} [params] Array of sql parameters.
+     * @return {Promise<any>} Promise resolved when done.
+     */
+    deleteRecordsSelect(table: string, select='', params?: any[]) : Promise<any> {
+        if (select) {
+            select = 'WHERE ' + select;
+        }
+
+        return this.execute(`DELETE FROM ${table} ${select}`, params);
+
+    }
+
+    /**
+     * Execute a SQL query.
+     *
+     * @param {string} sql SQL query to execute.
+     * @param {any[]} params Query parameters.
+     * @return {Promise<any>} Promise resolved with the result.
+     */
+    protected execute(sql: string, params?: any[]) : Promise<any> {
+        return this.ready().then(() => {
+            return this.db.executeSql(sql, params);
+        });
+    }
+
+    /**
+     * Execute a set of SQL queries. This operation is atomic.
+     *
+     * @param {any[]} sqlStatements SQL statements to execute.
+     * @return {Promise<any>} Promise resolved with the result.
+     */
+    protected executeBatch(sqlStatements: any[]) : Promise<any> {
+        return this.ready().then(() => {
+            return this.db.sqlBatch(sqlStatements);
+        });
+    }
+
+    /**
+     * Get a single field value from a table record where all the given conditions met.
+     *
+     * @param {string} table The table to query.
+     * @param {string} field The field to return the value of.
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @return {Promise<any>} Promise resolved with the field's value.
+     */
+    getField(table: string, field: string, conditions?: object) : Promise<any> {
+        let selectAndParams = this.whereClause(conditions);
+        return this.getFieldSelect(table, field, selectAndParams[0], selectAndParams[1]);
+    }
+
+    /**
+     * Get a single field value from a table record which match a particular WHERE clause.
+     *
+     * @param {string} table The table to query.
+     * @param {string} field The field to return the value of.
+     * @param {string} [select=''] A fragment of SQL to be used in a where clause returning one row with one column.
+     * @param {any[]} [params] Array of sql parameters.
+     * @return {Promise<any>} Promise resolved with the field's value.
+     */
+    getFieldSelect(table: string, field: string, select='', params?: any[]) : Promise<any> {
+        if (select) {
+            select = 'WHERE ' + select;
+        }
+
+        return this.getFieldSql(`SELECT ${field} FROM ${table} ${select}`, params);
+    }
+
+    /**
+     * Get a single field value (first field) using a SQL statement.
+     *
+     * @param {string} sql The SQL query returning one row with one column.
+     * @param {any[]} [params] An array of sql parameters.
+     * @return {Promise<any>} Promise resolved with the field's value.
+     */
+    getFieldSql(sql: string, params?: any[]) : Promise<any> {
+        return this.getRecordSql(sql, params).then((record) => {
+            if (!record) {
+                return Promise.reject(null);
+            }
+
+            // Return the first property.
+            return record[Object.keys(record)[0]];
+        });
+    }
+
+    /**
+     * Constructs 'IN()' or '=' sql fragment
+     *
+     * @param {any} items A single value or array of values for the expression. It doesn't accept objects.
+     * @param {boolean} [equal=true] True means we want to equate to the constructed expression.
+     * @param {any} [onEmptyItems] This defines the behavior when the array of items provided is empty. Defaults to false,
+     *              meaning throw exceptions. Other values will become part of the returned SQL fragment.
+     * @return {any[]} A list containing the constructed sql fragment and an array of parameters.
+     */
+    getInOrEqual(items: any, equal=true, onEmptyItems?: any) : any[] {
+        let sql,
+            params;
+
+        if (typeof onEmptyItems == 'undefined') {
+            onEmptyItems = false;
+        }
+
+        // Default behavior, return empty data on empty array.
+        if (Array.isArray(items) && !items.length && onEmptyItems === false) {
+            return ['', []];
+        }
+
+        // Handle onEmptyItems on empty array of items.
+        if (Array.isArray(items) && !items.length) {
+            if (onEmptyItems === null) { // Special case, NULL value.
+                sql = equal ? ' IS NULL' : ' IS NOT NULL';
+                return [sql, []];
+            } else {
+                items = [onEmptyItems]; // Rest of cases, prepare items for processing.
+            }
+        }
+
+        if (!Array.isArray(items) || items.length == 1) {
+            sql = equal ? '= ?' : '<> ?';
+            params = Array.isArray(items) ? items : [items];
+        } else {
+            sql = (equal ? '' : 'NOT ') +  'IN (' + ',?'.repeat(items.length).substr(1) + ')';
+            params = items;
+        }
+
+        return [sql, params];
+    }
+
+    /**
+     * Get the database name.
+     *
+     * @return {string} Database name.
+     */
+    getName() : string {
+        return this.name;
+    }
+
+    /**
+     * Get a single database record where all the given conditions met.
+     *
+     * @param {string} table The table to query.
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @param {string} [fields='*'] A comma separated list of fields to return.
+     * @return {Promise<any>} Promise resolved with the record, rejected if not found.
+     */
+    getRecord(table: string, conditions?: object, fields='*') : Promise<any> {
+        let selectAndParams = this.whereClause(conditions);
+        return this.getRecordSelect(table, selectAndParams[0], selectAndParams[1], fields);
+    }
+
+    /**
+     * Get a single database record as an object which match a particular WHERE clause.
+     *
+     * @param {string} table The table to query.
+     * @param {string} [select] A fragment of SQL to be used in a where clause in the SQL call.
+     * @param {any[]} [params] An array of sql parameters.
+     * @param {string} [fields='*'] A comma separated list of fields to return.
+     * @return {Promise<any>} Promise resolved with the record, rejected if not found.
+     */
+    getRecordSelect(table: string, select='', params=[], fields='*') : Promise<any> {
+        if (select) {
+            select = ' WHERE ' + select;
+        }
+
+        return this.getRecordSql(`SELECT ${fields} FROM ${table} ${select}`, params);
+    }
+
+    /**
+     * Get a single database record as an object using a SQL statement.
+     *
+     * The SQL statement should normally only return one record.
+     * It is recommended to use getRecordsSql() if more matches possible!
+     *
+     * @param {string} sql The SQL string you wish to be executed, should normally only return one record.
+     * @param {any[]} [params] List of sql parameters
+     * @return {Promise<any>} Promise resolved with the records.
+     */
+    getRecordSql(sql: string, params?: any[]) : Promise<any> {
+        return this.getRecordsSql(sql, params, 0, 1).then((result) => {
+            if (!result || !result.length) {
+                // Not found, reject.
+                return Promise.reject(null);
+            }
+
+            // Return only the first record.
+            return result[0];
+        });
+    }
+
+    /**
+     * Get a number of records where all the given conditions met.
+     *
+     * @param {string} table The table to query.
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @param {string} [sort=''] An order to sort the results in.
+     * @param {string} [fields='*'] A comma separated list of fields to return.
+     * @param {number} [limitFrom=0] Return a subset of records, starting at this point.
+     * @param {number} [limitNum=0] Return a subset comprising this many records in total.
+     * @return {Promise<any>} Promise resolved with the records.
+     */
+    getRecords(table: string, conditions?: object, sort='', fields='*', limitFrom=0, limitNum=0) : Promise<any> {
+        let selectAndParams = this.whereClause(conditions);
+        return this.getRecordsSelect(table, selectAndParams[0], selectAndParams[1], sort, fields, limitFrom, limitNum);
+    }
+
+    /**
+     * Get a number of records where one field match one list of values.
+     *
+     * @param {string} table The database table to be checked against.
+     * @param {string} field The name of a field.
+     * @param {any[]} values The values field might take.
+     * @param {string} [sort=''] An order to sort the results in.
+     * @param {string} [fields='*'] A comma separated list of fields to return.
+     * @param {number} [limitFrom=0] Return a subset of records, starting at this point.
+     * @param {number} [limitNum=0] Return a subset comprising this many records in total.
+     * @return {Promise<any>} Promise resolved with the records.
+     */
+    getRecordsList(table: string, field: string, values: any[], sort='', fields='*', limitFrom=0, limitNum=0) : Promise<any> {
+        let selectAndParams = this.whereClauseList(field, values);
+        return this.getRecordsSelect(table, selectAndParams[0], selectAndParams[1], sort, fields, limitFrom, limitNum);
+    }
+
+    /**
+     * Get a number of records which match a particular WHERE clause.
+     *
+     * @param {string} table The table to query.
+     * @param {string} [select] A fragment of SQL to be used in a where clause in the SQL call.
+     * @param {any[]} [params] An array of sql parameters.
+     * @param {string} [sort=''] An order to sort the results in.
+     * @param {string} [fields='*'] A comma separated list of fields to return.
+     * @param {number} [limitFrom=0] Return a subset of records, starting at this point.
+     * @param {number} [limitNum=0] Return a subset comprising this many records in total.
+     * @return {Promise<any>} Promise resolved with the records.
+     */
+    getRecordsSelect(table: string, select='', params=[], sort='', fields='*', limitFrom=0, limitNum=0) : Promise<any> {
+        if (select) {
+            select = ' WHERE ' + select;
+        }
+        if (sort) {
+            sort = ' ORDER BY ' + sort;
+        }
+
+        let sql = `SELECT ${fields} FROM ${table} ${select} ${sort}`;
+        return this.getRecordsSql(sql, params, limitFrom, limitNum);
+    }
+
+    /**
+     * Get a number of records using a SQL statement.
+     *
+     * @param {string} sql The SQL select query to execute.
+     * @param {any[]} [params] List of sql parameters
+     * @param {number} [limitFrom] Return a subset of records, starting at this point.
+     * @param {number} [limitNum] Return a subset comprising this many records.
+     * @return {Promise<any>} Promise resolved with the records.
+     */
+    getRecordsSql(sql: string, params?: any[], limitFrom?: number, limitNum?: number) : Promise<any> {
+        let limits = this.normaliseLimitFromNum(limitFrom, limitNum);
+
+        if (limits[0] || limits[1]) {
+            if (limits[1] < 1) {
+                limits[1] = Number.MAX_VALUE;
+            }
+            sql += ' LIMIT ' + limits[0] + ', ' + limits[1];
+        }
+
+        return this.execute(sql, params).then((result) => {
+            // Retrieve the records.
+            let records = [];
+            for (let i = 0; i < result.rows.length; i++) {
+                records.push(result.rows.item(i));
+            }
+            return records;
+        });
+    }
+
+    /**
+     * Given a data object, returns the SQL query and the params to insert that record.
+     *
+     * @param {string} table The database table.
+     * @param {object} data A data object with values for one or more fields in the record.
+     * @return {any[]} Array with the SQL query and the params.
+     */
+    protected getSqlInsertQuery(table: string, data: object) : any[] {
+        let keys = Object.keys(data),
+            fields = keys.join(','),
+            questionMarks = ',?'.repeat(keys.length).substr(1);
+
+        return [
+            `INSERT INTO ${table} (${fields}) VALUES (${questionMarks})`,
+            keys.map(key => data[key])
+        ];
+    }
+
+    /**
+     * Initialize the database.
+     */
+    init() : void {
+        this.promise = this.platform.ready().then(() => {
+            return this.sqlite.create({
+                name: this.name,
+                location: 'default'
+            });
+        }).then((db: SQLiteObject) => {
+            this.db = db;
+        });
+    }
+
+    /**
+     * Insert or update a record.
+     *
+     * @param {string} table The database table.
+     * @param {object} data An object with the fields to insert/update: fieldname=>fieldvalue.
+     * @param {object} conditions The conditions to check if the record already exists.
+     * @return {Promise<any>} Promise resolved with done.
+     */
+    insertOrUpdateRecord(table: string, data: object, conditions: object) : Promise<any> {
+        return this.getRecord(table, conditions || data).then(() => {
+            // It exists, update it.
+            return this.updateRecords(table, data, conditions);
+        }).catch(() => {
+            // Doesn't exist, insert it.
+            return this.insertRecord(table, data);
+        });
+    }
+
+    /**
+     * Insert a record into a table and return the "rowId" field.
+     *
+     * @param {string} table The database table to be inserted into.
+     * @param {object} data A data object with values for one or more fields in the record.
+     * @return {Promise<number>} Promise resolved with new rowId. Please notice this rowId is internal from SQLite.
+     */
+    insertRecord(table: string, data: object) : Promise<number> {
+        let sqlAndParams = this.getSqlInsertQuery(table, data);
+
+        return this.execute(sqlAndParams[0], sqlAndParams[1]).then((result) => {
+            return result.insertId;
+        });
+    }
+
+    /**
+     * Insert multiple records into database as fast as possible.
+     *
+     * @param {string} table The database table to be inserted into.
+     * @param {object[]} dataObjects List of objects to be inserted.
+     * @return {Promise<any>} Promise resolved when done.
+     */
+    insertRecords(table: string, dataObjects: object[]) : Promise<any> {
+        if (!Array.isArray(dataObjects)) {
+            return Promise.reject(null);
+        }
+
+        let statements = [];
+
+        dataObjects.forEach((dataObject) => {
+            statements.push(this.getSqlInsertQuery(table, dataObject));
+        });
+
+        return this.executeBatch(statements);
+    }
+
+    /**
+     * Ensures that limit params are numeric and positive integers, to be passed to the database.
+     * We explicitly treat null, '' and -1 as 0 in order to provide compatibility with how limit
+     * values have been passed historically.
+     *
+     * @param {any} limitFrom Where to start results from.
+     * @param {any} limitNum How many results to return.
+     * @return {number[]} Normalised limit params in array: [limitFrom, limitNum].
+     */
+    normaliseLimitFromNum(limitFrom: any, limitNum: any) : number[] {
+        // We explicilty treat these cases as 0.
+        if (limitFrom === null || limitFrom === '' || limitFrom === -1) {
+            limitFrom = 0;
+        }
+        if (limitNum === null || limitNum === '' || limitNum === -1) {
+            limitNum = 0;
+        }
+
+        limitFrom = parseInt(limitFrom, 10);
+        limitNum  = parseInt(limitNum, 10);
+        limitFrom = Math.max(0, limitFrom);
+        limitNum  = Math.max(0, limitNum);
+
+        return [limitFrom, limitNum];
+    }
+
+    /**
+     * Open the database. Only needed if it was closed before, a database is automatically opened when created.
+     */
+    open() {
+        return this.ready().then(() => {
+            return this.db.open();
+        });
+    }
+
+    /**
+     * Wait for the DB to be ready.
+     *
+     * @return {Promise<void>} Promise resolved when ready.
+     */
+    ready() : Promise<void> {
+        return this.promise;
+    }
+
+    /**
+     * Test whether a record exists in a table where all the given conditions met.
+     *
+     * @param {string} table The table to check.
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @return {Promise<void>} Promise resolved if exists, rejected otherwise.
+     */
+    recordExists(table: string, conditions?: object) : Promise<void> {
+        return this.getRecord(table, conditions).then((record) => {
+            if (!record) {
+                return Promise.reject(null);
+            }
+        });
+    }
+
+    /**
+     * Test whether any records exists in a table which match a particular WHERE clause.
+     *
+     * @param {string} table The table to query.
+     * @param {string} [select] A fragment of SQL to be used in a where clause in the SQL call.
+     * @param {any[]} [params] An array of sql parameters.
+     * @return {Promise<any>} Promise resolved if exists, rejected otherwise.
+     */
+    recordExistsSelect(table: string, select='', params=[]) : Promise<any> {
+        return this.getRecordSelect(table, select, params).then((record) => {
+            if (!record) {
+                return Promise.reject(null);
+            }
+        });
+    }
+
+    /**
+     * Test whether a SQL SELECT statement returns any records.
+     *
+     * @param {string} sql The SQL query returning one row with one column.
+     * @param {any[]} [params] An array of sql parameters.
+     * @return {Promise<any>} Promise resolved if exists, rejected otherwise.
+     */
+    recordExistsSql(sql: string, params?: any[]) : Promise<any> {
+        return this.getRecordSql(sql, params).then((record) => {
+            if (!record) {
+                return Promise.reject(null);
+            }
+        });
+    }
+
+    /**
+     * Update one or more records in a table.
+     *
+     * @param {string} string table The database table to update.
+     * @param {any} data An object with the fields to update: fieldname=>fieldvalue.
+     * @param {any} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @return {Promise<any>} Promise resolved when updated.
+     */
+    updateRecords(table: string, data: any, conditions?: any) : Promise<any> {
+
+        if (!data || !Object.keys(data).length) {
+            // No fields to update, consider it's done.
+            return Promise.resolve();
+        }
+
+        let whereAndParams = this.whereClause(conditions),
+            sets = [],
+            sql,
+            params;
+
+        for (var key in data) {
+            sets.push(`${key} = ?`);
+        }
+
+        sql = `UPDATE ${table} SET ${sets.join(', ')} WHERE ${whereAndParams[0]}`;
+        // Create the list of params using the "data" object and the params for the where clause.
+        params = Object.keys(data).map(key => data[key]).concat(whereAndParams[1]);
+
+        return this.execute(sql, params);
+    }
+
+    /**
+     * Returns the SQL WHERE conditions.
+     *
+     * @param {object} [conditions] The conditions to build the where clause. Must not contain numeric indexes.
+     * @return {any[]} An array list containing sql 'where' part and 'params'.
+     */
+    whereClause(conditions={}) : any[] {
+        if (!conditions || !Object.keys(conditions).length) {
+            return ['', []];
+        }
+
+        let where = [],
+            params = [];
+
+        for (let key in conditions) {
+            let value = conditions[key];
+
+            if (typeof value == 'undefined' || value === null) {
+                where.push(key + ' IS NULL');
+            } else {
+                where.push(key + ' = ?');
+                params.push(value);
+            }
+        }
+
+        return [where.join(' AND '), params];
+    }
+
+    /**
+     * Returns SQL WHERE conditions for the ..._list group of methods.
+     *
+     * @param {string} field The name of a field.
+     * @param {any[]} values The values field might take.
+     * @return {any[]} An array containing sql 'where' part and 'params'.
+     */
+    whereClauseList(field: string, values: any[]) : any[] {
+        if (!values || !values.length) {
+            return ["1 = 2", []]; // Fake condition, won't return rows ever.
+        }
+
+        let params = [],
+            select = '';
+
+        values.forEach((value) => {
+            if (typeof value == 'boolean') {
+                value = Number(value);
+            }
+
+            if (typeof value == 'undefined' || value === null) {
+                select = field + ' IS NULL';
+            } else {
+                params.push(value);
+            }
+        });
+
+        if (params && params.length) {
+            if (select !== '') {
+                select = select + ' OR ';
+            }
+
+            if (params.length == 1) {
+                select = select + field + ' = ?';
+            } else {
+                let questionMarks = ',?'.repeat(params.length).substr(1);
+                select = select + field + ' IN (' + questionMarks + ')';
+            }
+        }
+
+        return [select, params];
+    }
+}

src/providers/db.ts

@@ -0,0 +1,74 @@
+// (C) Copyright 2015 Martin Dougiamas
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { Injectable } from '@angular/core';
+import { SQLite } from '@ionic-native/sqlite';
+import { Platform } from 'ionic-angular';
+import { SQLiteDB } from '../classes/sqlitedb';
+
+/**
+ * This service allows interacting with the local database to store and retrieve data.
+ */
+@Injectable()
+export class CoreDbProvider {
+
+    dbInstances = {};
+
+    constructor(private sqlite: SQLite, private platform: Platform) {}
+
+    /**
+     * Get or create a database object.
+     *
+     * The database objects are cached statically.
+     *
+     * @param {string} name DB name.
+     * @param {boolean} forceNew True if it should always create a new instance.
+     * @return {SQLiteDB} DB.
+     */
+    getDB(name: string, forceNew: boolean) : SQLiteDB {
+        if (typeof this.dbInstances[name] === 'undefined' || forceNew) {
+            this.dbInstances[name] = new SQLiteDB(name, this.sqlite, this.platform);
+        }
+        return this.dbInstances[name];
+    }
+
+    /**
+     * Delete a DB.
+     *
+     * @param {string} name DB name.
+     * @return {Promise<any>} Promise resolved when the DB is deleted.
+     */
+    deleteDB(name: string) : Promise<any> {
+        let promise;
+
+        if (typeof this.dbInstances[name] != 'undefined') {
+            // Close the database first.
+            promise = this.dbInstances[name].close();
+        } else {
+            promise = Promise.resolve();
+        }
+
+        return promise.then(() => {
+            delete this.dbInstances[name];
+
+            return this.sqlite.deleteDatabase({
+                name: name,
+                location: 'default'
+            });
+        });
+    }
+}
+
+
+