IdentifiableJsonMySqlPersistence[T,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.

Implements: 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

InheritIdentifiableJsonMySqlPersistence

Creates a new instance of the persistence component.

InheritIdentifiableJsonMySqlPersistence[T any, K any](overrides IMySqlPersistenceOverrides[T], tableName string) *IdentifiableJsonMySqlPersistence[T, K]

Instance methods

ConvertFromPublic

Converts object value from public to internal format.

`(c *IdentifiableJsonMySqlPersistence[T, K]) ConvertFromPublic(value T) (map[string]any, error)

  • value: T - object in public format to convert.
  • returns: (map[string]any, error) - converted object in internal format.

ConvertToPublic

Converts object value from internal to public format.

(c *IdentifiableJsonMySqlPersistence[T, K]) ConvertToPublic(rows *sql.Rows) (T, error)

  • rows: *sql.Rows - object in internal format to convert.
  • returns: (T, error) - converted object in public format.

EnsureTable

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

(c *IdentifiableJsonMySqlPersistence[T, K]) EnsureTable(idType string, dataType string)

  • 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.

(c *IdentifiableJsonMySqlPersistence[T, K]) UpdatePartially(ctx context.Context, context IContext, id K, data AnyValueMap) (result T, err error)

  • ctx: context.Context - operation context.
  • 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: (result T, err error) - updated item

Examples

type MyMySqlPersistence struct {
	*persist.IdentifiableJsonMySqlPersistence[MyData, string]
}

func NewMyMySqlPersistence() *MyMySqlPersistence {
	c := &MyMySqlPersistence{}
	c.IdentifiableJsonMySqlPersistence = persist.InheritIdentifiableJsonMySqlPersistence[MyData, string](c, "mydata")
	return c
}

func (c *MyMySqlPersistence) DefineSchema() {
	c.ClearSchema()
	c.EnsureTable("", "")
	c.EnsureSchema("ALTER TABLE `" + c.TableName + "` ADD `data_key` VARCHAR(50) AS (JSON_UNQUOTE(`data`->\"$.key\"))")
	c.EnsureIndex(c.TableName+"_json_key", map[string]string{"data_key": "1"}, map[string]string{"unique": "true"})
}

func (c *MyMySqlPersistence) GetPageByFilter(ctx context.Context, context IContext,
	filter cdata.FilterParams, paging cdata.PagingParams) (page cdata.DataPage[MyData], err error) {

	key, ok := filter.GetAsNullableString("Key")
	filterObj := ""
	if ok && key != "" {
		filterObj += "data->'$.key'='" + key + "'"
	}

	return c.IdentifiableJsonMySqlPersistence.GetPageByFilter(ctx, context,
		filterObj, paging,
		"", "",
	)
}

func main() {
	persistence := NewMyMySqlPersistence()
	persistence.Configure(context.Background(), cconf.NewConfigParamsFromTuples(
		"host", "localhost",
		"port", 27017,
	))
	err := persitence.Open(context.Background(), "123")

	item, err := persistence.Create(context.Background(), "123", Mydata{Id: "1", Name: "ABC"})
	page, err := persistence.GetPageByFilter("123", *NewFilterParamsFromTuples("name", "ABC"), nil)

	fmt.Println(page.data) // Result: { id: "1", name: "ABC" }

	res, err := persistence.DeleteById(context.Background(),"123", "1")
}