The Timeline model is designed to store message data. This model can meet the requirements of messaging processes, such as message order preservation, storage of large numbers of messages, and real-time synchronization. This model also supports full-text search and Boolean query. This model is suitable for storing message data that is generated from instant messaging (IM) applications and feed streams.
Architecture
The Timeline model provides clear core modules in a simple design. You can easily use the Timeline model to implement your services in different methods as required. The architecture of the model includes the following components:
Store: a unit used to store Timeline data. A store is similar to a table in database services.
Identifier: an identifier used to identify Timeline data.
Meta: the metadata used to describe Timeline data. The metadata is stored in a free-schema structure and can contain any column.
Queue: stores all messages in a Timeline.
SequenceId: the serial number of a message body in the Queue. The SequenceId values must be incremental and unique. The Timeline model generates SequenceId values by using an auto-increment column. You can also specify SequenceId values manually.
Message: the message body in the Timeline. The message is stored in a free-schema structure and can contain any column.
Index: includes Meta Index and Message Index. You can customize indexes for any columns in Meta or Message to provide Boolean query.
Features
The Timeline model supports the following features:
Management of Meta data and messages, including basic data operations such as create, read, update, and delete operations.
Boolean query and full-text search for Meta data and messages.
Two configuration methods for SequenceId values: auto-increment column and manual setting.
Timeline Identifier that contains multiple columns.
Compatibility with the Timeline model V1.x. The TimelineMessageForV1 examples of the Timeline model can be used to read messages from and write messages to the Timeline model V1.x.
Usage notes
To import dependencies of Tablestore SDK for Java to a Maven project, perform the following operation based on the version of Tablestore SDK for Java:
For Tablestore SDK for Java V4.12.1 or later in which the Timeline model is incorporated, import Tablestore dependencies.
<dependency> <groupId>com.aliyun.openservices</groupId> <artifactId>tablestore</artifactId> <version>4.12.1</version> </dependency>For Tablestore SDK for Java earlier than V4.12.1, import Tablestore dependencies and Timeline model dependencies.
<dependency> <groupId>com.aliyun.openservices.tablestore</groupId> <artifactId>Timeline</artifactId> <version>2.0.0</version> </dependency>