IdentifiableJsonSqlitePersistence<T extends IIdentifiable<K>, K>

Extends: IdentifiableSqlitePersistence<T, K>

Description

Important points

• The data items must implement the IIdentifiable interface.
• 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) SQLite table name
• schema: (optional) SQLite schema name
• connection(s):
  • discovery_key: (optional) key to retrieve the connection from IDiscovery
  • database: database file path
  • uri: resource URI with file:// protocol

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 an 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 an 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 a 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 a few selected fields in a data item.

public updatePartially(context: IContext, id: K, data: AnyValueMap): Promise<T>

• context: IContext - (optional) a context to trace execution through a 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 MySqlitePersistence extends IdentifiableSqliteJsonPersistence<MyData, string> {
    public constructor() {
        super("mydata");
    }
    
    protected defineSchema(): void {
        this.clearSchema();
        this.ensureTable();
        this.ensureSchema("CREATE UNIQUE INDEX IF NOT EXISTS \"" + this._tableName + "_json_key\" ON dummies_json (JSON_EXTRACT(data, '$.name'))");
    }
    
    private composeFilter(filter: FilterParams): any {
        filter = filter || new FilterParams();
        let name = filter.getAsNullableString('name');

        let filterCondition: string = null;
        if (name != null)
            filterCondition = "JSON_EXTRACT(data, '$.name')='" + name + "'";
    
        return filterCondition;
    }
    public getPageByFilter(context: IContext, filter: FilterParams,
        paging: PagingParams): Promise<DataPage<MyData>> {
        return super.getPageByFilter(context, this.composeFilter(filter), paging, null, null);
    }
}

let persistence = new MySqlitePersistence();
persistence.configure(ConfigParams.fromTuples(
    "connection.database", "./data/mydb.db"
));

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" }
await persistence.deleteById("123", "1");