IdentifiableJsonMySqlPersistence<T extends IIdentifiable<K>, K>

Abstract persistence component that stores data in MySQL in JSON or JSONB fields and implements a number of CRUD operations over data items with unique ids.

Extends: IdentifiableMySqlPersistence<T, K>

Description

The IdentifiableJsonMySqlPersistence class allows you to create persistence components that store data in JSON or JSONB fields and implement a number of CRUD operations over data items with unique ids.

Important points

  • The JSON table has only two fields: id and data.
  • In basic scenarios child classes shall only override getPageByFilter, getListByFilter or deleteByFilter operations with a specific filter function.
  • All other operations can be used out of the box.
  • In complex scenarios child classes can implement additional operations by accessing this._collection and this._model properties.

Configuration parameters

  • collection: (optional) MySQL collection name

connection(s):

  • discovery_key: (optional) key to retrieve the connection from IDiscovery
  • host: host name or IP address
  • port: port number (default: 27017)
  • uri: resource URI or connection string with all parameters in it

credential(s):

  • store_key: (optional) key to retrieve the credentials from ICredentialStore
  • username: (optional) username
  • password: (optional) user’s password

options:

  • connect_timeout: (optional) number of milliseconds to wait before timing out when connecting a new client (default: 0)
  • idle_timeout: (optional) number of milliseconds a client must sit idle in the pool and not be checked out (default: 10000)
  • max_pool_size: (optional) maximum number of clients the pool can contain (default: 10)

References

  • *:logger:*:*:1.0 - (optional) ILogger components to pass log messages
  • *:discovery:*:*:1.0 - (optional) IDiscovery services
  • *:credential-store:*:*:1.0 - (optional) ICredentialStore to resolve credentials

Constructors

Creates a new instance of the persistence component.

public constructor(tableName: string)

  • tableName: string - (optional) collection name.

Instance methods

convertFromPublic

Converts object value from public to internal format.

protected convertFromPublic(value: any): any

  • value: any - object in public format to convert.
  • returns: any - converted object in internal format.

convertToPublic

Converts object value from internal to public format.

protected convertToPublic(value: any): any

  • value: any - object in internal format to convert.
  • returns: any - converted object in public format.

ensureTable

Adds DML statement to automatically create a JSON(B) table

protected ensureTable(idType: string = ‘VARCHAR(32)’, dataType: string = ‘JSON’)

  • idType: string - type of the id column (default: VARCHAR(32))
  • dataType: string - type of the data column (default: JSON)

updatePartially

Updates only few selected fields in a data item.

public updatePartially(correlationId: string, id: K, data: AnyValueMap): Promise<T>

  • correlationId: string - (optional) transaction id used to trace execution through the call chain.
  • id: K - id of the data item to be updated.
  • data: AnyValueMap - map with fields to be updated.
  • return: Promise<T> - updated item

Examples

class MyMySqlPersistence extends IdentifiableMySqlJsonPersistence<MyData, string> {
    public constructor() {
        base("mydata", new MyDataMySqlSchema());
    }

    private composeFilter(filter: FilterParams): any {
        filter = filter || new FilterParams();
        let criteria = [];
        let name = filter.getAsNullableString('name');
        if (name != null)
            criteria.push({ name: name });
        return criteria.length > 0 ? { $and: criteria } : null;
    }

    public getPageByFilter(correlationId: string, filter: FilterParams, paging: PagingParams,
        callback: (err: any, page: DataPage<MyData>) => void): void {
        base.getPageByFilter(correlationId, this.composeFilter(filter), paging, null, null, callback);
    }
}

let persistence = new MyMySqlPersistence();
persistence.configure(ConfigParams.fromTuples(
    "host", "localhost",
    "port", 27017
));

persitence.open("123", (err) => {
    ...
});

persistence.create("123", { id: "1", name: "ABC" }, (err, item) => {
    persistence.getPageByFilter(
        "123",
        FilterParams.fromTuples("name", "ABC"),
        null,
        (err, page) => {
            console.log(page.data);          // Result: { id: "1", name: "ABC" }
            persistence.deleteById("123", "1", (err, item) => {
               ...
            });
        }
    )
});