Sequence

Overview

Module

• package: @aerokit/sdk/db
• source: db/sequence.ts
• last updated:

This module provides a Sequence class for managing database sequences in the Dirigible environment. The Sequence class offers static methods to retrieve the next value from a sequence, create new sequences, and drop existing sequences. It abstracts the underlying database interactions, allowing developers to work with sequences in a consistent manner across different database systems supported by Dirigible.

Key Features

• Retrieve the next value from a specified database sequence.
• Create new sequences with optional starting values.
• Drop existing sequences when they are no longer needed.
• Support for specifying datasource names to target specific database connections.

Use Cases

• Generating unique identifiers for records in a database table using sequences.
• Managing database sequences as part of application setup or migration processes.
• Abstracting sequence management to allow for easier maintenance and potential database engine changes in the future.

Example Usage

import { Sequence } from "@aerokit/sdk/db";

// Create a new sequence named "user_id_seq" starting at 1000
Sequence.create("user_id_seq", 1000);

// Get the next value from the "user_id_seq" sequence
const nextUserId = Sequence.nextval("user_id_seq");
console.log(nextUserId); // Output: 1000

// Drop the "user_id_seq" sequence when it's no longer needed
Sequence.drop("user_id_seq");

Classes

Sequence

nextval()

Retrieves the next available value from a specified sequence.

static nextval(sequence: string, tableName: string, datasourceName: string): number;

Parameter	Type	Description
sequence	string	The name of the database sequence.
tableName	string	Optional: The name of the table associated with the sequence (depends on database dialect/facade implementation).
datasourceName	string	Optional: The name of the database connection to use.

Returns

• Type: number
• Description: The next sequence value as a number.

create()

Creates a new database sequence.

static create(sequence: string, start: number, datasourceName: string): void;

Parameter	Type	Description
sequence	string	The name of the sequence to create.
start	number	Optional: The starting value for the sequence (defaults to 1 if not provided).
datasourceName	string	Optional: The name of the database connection to use.

Returns

• Type: void
• Description:

drop()

Drops (deletes) an existing database sequence.

static drop(sequence: string, datasourceName: string): void;

Parameter	Type	Description
sequence	string	The name of the sequence to drop.
datasourceName	string	Optional: The name of the database connection to use.

Returns

• Type: void
• Description: