IdentifiableJsonMySqlPersistence<T extends IIdentifiable<K>, K>

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

• table: (optional) MySQL table name
• schema: (optional) MySQL schema 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, schemaName?: string)

• tableName: string - (optional) collection name.
• schemaName: string - (optional) a schema 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() {
        super("mydata", new MyDataMySqlSchema());
    }
    
    protected defineSchema(): void {
        this.clearSchema();
        this.ensureTable();
        this.ensureSchema('ALTER TABLE `' + this._tableName + '` ADD `data_key` VARCHAR(50) AS (JSON_UNQUOTE(`data`->"$.key"))');
        this.ensureIndex(this._tableName + '_json_key', { "data_key": 1 }, { unique: true });
    }

    private composeFilter(filter: FilterParams): any {
        filter = filter || new FilterParams();
        let name = filter.getAsNullableString('name');

        let filterCondition: string = null;
        if (name != null) {
            filterCondition += "data->name='" + name + "'";
        }
    
        return filterCondition;
    }

    public getPageByFilter(correlationId: string, filter: FilterParams, paging: PagingParams): Promise<DataPage<MyData>> {
        return super.getPageByFilter(correlationId, this.composeFilter(filter), paging, null, null);
    }
}

let persistence = new MyMySqlPersistence();
persistence.configure(ConfigParams.fromTuples(
    "connection.host", "localhost",
    "connection.port", 5432,
    "credential.username", "mysql",
    "credential.password", "mysql",
    "connection.database", "mytestobjects"
));

await persitence.open("123");

let item = await persistence.create("123", { id: "1", name: "ABC" });

let page = await persistence.getPageByFilter(
    "123",
    FilterParams.fromTuples("name", "ABC"),
    null,
)

console.log(page.data);     // Result: { id: "1", name: "ABC" }
item = await persistence.deleteById("123", "1");