Node-jql-core NPM

node-jql-core

This is a SQL database mainly designed for providing an interface for JSON processing with the SQL syntax. It works with the syntax library node-jql

Memory Engine

PAY ATTENTION

Note: It's still under development. Please avoid using it in production

Note: It's not fully optimized, and may be slow. Please avoid doing intensive computation with this engine

Note: NodeJS version 8 or higher is highly recommended due to the native support of async/await

Usage

(async () => {
  // initialize core
  const core = new ApplicationCore({ defaultEngine: new InMemoryDatabaseEngine({ logger: new Logger('InMemoryDatabaseEngine') }) })
  await core.init()

  // create session
  const session = core.createSession()

  /**
   * USE database
   */
  session.use(string)

  /**
   * ID of the last running task
   */
  session.lastTaskId

  /**
   * CRETAE, INSERT, UPDATE, ALTER etc.
   */
  session.update(JQL)

  /**
   * Predict SELECT result structure
   */
  session.predict(JQL)

  /**
   * SELECT
   */
  session.query(JQL)

  /**
   * Kill running task
   */
  session.kill(string)

  /**
   * Close the session
   */
  session.close(boolean?)
})()

Custom Engine

You can develop your custom engine.

Please check CancelablePromise

abstract class DatabaseEngine {
  protected initing = false
  protected inited = false

  /**
   * Initialize the engine
   */
  public abstract async init(): Promise<void>

  /**
   * Retrieve all rows from a table
   * @param database [string] database name
   * @param table [string] table name
   */
  public abstract retrieveRowsFor(database: string, table: string): CancelablePromise<any[]>

  /**
   * Get the row count of a table
   * @param database [string] database name
   * @param table [string] table name
   */
  public abstract getCountOf(database: string, table: string): CancelablePromise<number>

  /**
   * Create a database
   * @param name [string]
   */
  public abstract createDatabase(name: string): TaskFn<IUpdateResult>

  /**
   * Drop a database
   * @param name [string]
   */
  public abstract dropDatabase(name: string): TaskFn<IUpdateResult>

  /**
   * Execute an UPDATE JQL
   * @param jql [JQL]
   */
  public abstract executeUpdate(jql: JQL): TaskFn<IUpdateResult>

  /**
   * Execute a SELECT JQL
   * @param jql [AnalyzedQuery]
   */
  public abstract executeQuery(jql: AnalyzedQuery): TaskFn<IQueryResult>
}

type TaskFn<T> = (task: Task<T>) => CancelablePromise<T>

class Task {
  /**
   * Task ID
   */
  public readonly id = uuid()

  /**
   * Task that can be canceled
   */
  public readonly promise: CancelablePromise<T>

  /**
   * Start time of the task
   */
  public readonly startFrom = Date.now()

  /**
   * Task status
   */
  public statusCode = StatusCode.PREPARING
}