Created
July 14, 2020 02:26
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| import { Sequelize } from 'sequelize'; | |
| import { ConfigurationManager } from '../config'; | |
| export class DbConnector { | |
| private static connectorInstance: DbConnector; | |
| private readonly connection: Sequelize; | |
| /** | |
| * Returns an instance of DBConnector, which might or might not have been synced with the DB. | |
| * It is currently the user"s prerogative to connect to the database. | |
| */ | |
| static getSingletonInstance(): DbConnector { | |
| return DbConnector.connectorInstance = new DbConnector(); | |
| } | |
| /** | |
| * Returns the result set if rows exist, else null | |
| * @param spQuery Sp with params | |
| * @param parameterValues param values as json object | |
| */ | |
| async executeQuery<T>(spQuery: string, parameterValues: any, minimumNumberOfRows = 1): Promise<Array<T>> { | |
| return new Promise<Array<T>>((resolve, reject) => { | |
| this.connection.query(spQuery, { replacements: parameterValues }).then(([results]: Array<any>) => { | |
| const hasRows = this.doesQueryHaveResults(results, minimumNumberOfRows); | |
| resolve(hasRows ? (JSON.parse(JSON.stringify(results)) as Array<T>) : undefined as any); | |
| }).catch(reject); | |
| }); | |
| } | |
| /** | |
| * Returns the result of the query | |
| * Note: All SPs return a value for a create/update, hence there is no need to check for number of rows returned. | |
| * @param spQuery Sp with params | |
| * @param parameterValues param values as json object | |
| */ | |
| async executeUpdate<T>(spQuery: string, parameterValues: any): Promise<Array<T>> { | |
| return new Promise<Array<T>>((resolve, reject) => { | |
| this.connection.query(spQuery, { replacements: parameterValues }).then(([results]: Array<any>) => { | |
| resolve(JSON.parse(JSON.stringify(results)) as Array<T>); | |
| }).catch(reject); | |
| }); | |
| } | |
| /** | |
| * Checking the executed quary results | |
| * @param results Result json | |
| * @param minimumNumberOfRows minimum number of rows | |
| */ | |
| doesQueryHaveResults = (results: any, minimumNumberOfRows: number) => results && (results.length >= minimumNumberOfRows); | |
| private constructor() { | |
| this.connection = new Sequelize(ConfigurationManager.getSingletonInstance().connectionString, { | |
| dialectOptions: { | |
| options: { | |
| encrypt: true | |
| } | |
| } | |
| }); | |
| } | |
| } |
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