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)

Note: the options below are currently not supported.

• 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.

IdentifiableJsonMySqlPersistence(String? tableName, String? schemaName) : super(tableName, schemaName)

• tableName: string - (optional) collection name.
• schemaName: string - (optional) a schema name.

Instance methods

convertFromPublic

Converts object value from public to internal format.

dynamic convertFromPublic_(value)

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

convertToPublic

Converts object value from internal to public format.

dynamic convertToPublic_(value)

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

ensureTable

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

void ensureTable_({String idType = ‘VARCHAR(32)’, String dataType = ‘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.

Future<T?> updatePartially(IContext? context, K? id, AnyValueMap? data) async

• 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: Future<T> - updated item

Examples

class MyMySqlPersistence extends IdentifiableJsonMySqlPersistence<MyData, String> {
       MyMySqlPersistence() : super('mydata', null);

       @override
       void defineSchema_() {
         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});
       }

       @override
       Future<DataPage<MyData>> getPageByFilter(
           IContext? context, FilterParams? filter, PagingParams? paging) async {
         filter = filter ?? new FilterParams();
         var key = filter.getAsNullableString('key');

         var filterCondition = null;
         if (key != null) {
           filterCondition += "`key`='" + key + "'";
         }

         return super
             .getPageByFilter_(context, filterCondition, paging, null, null);
       }
     }

     var persistence = MyMySqlPersistence();
     persistence
         .configure(ConfigParams.fromTuples(["host", "localhost", "port", 27017]));
     await persistence.open(null);
     var item = await persistence.create(null, MyData());
     var page = await persistence.getPageByFilter(
         null, FilterParams.fromTuples(["key", "ABC"]), null);
     print(page.data);
     var deleted = await persistence.deleteById(null, '1');