IdentifiableJsonMySqlPersistence[T,K]

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]

• overrides: IMySqlPersistenceOverrides[T] - References to override virtual methods
• tableName: string - (optional) a table name.

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, correlationId string, id K, data AnyValueMap) (result T, err error)

• ctx: context.Context - operation context.
• 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: (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, correlationId string,
	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, correlationId,
		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")
}