Azure Storage Table API

Welcome to the comprehensive documentation for the Azure Storage Table API. This API allows you to store and query large amounts of structured, non-relational data.

Overview

Azure Table storage is a NoSQL key-attribute store that allows you to store large amounts of structured data. The Table service is ideal for applications that need a flexible schema and can scale massively. Data in Table storage is stored as collections of entities, where each entity is a set of properties. An entity is like a row, and a property is like a column.

Key Concepts

• Tables: A collection of entities. A table does not enforce a schema, meaning different entities within the same table can have different sets of properties.
• Entities: A set of properties. An entity is analogous to a row in a database. Each entity has a primary key, which consists of a PartitionKey and a RowKey.
• Properties: A name-value pair. A property is analogous to a column. Each entity can have up to 252 properties, plus the four system properties (PartitionKey, RowKey, Timestamp, Etag).
• PartitionKey: Distributes data across multiple storage nodes for scalability. Entities with the same PartitionKey are guaranteed to be co-located on the same storage node.
• RowKey: Uniquely identifies an entity within a partition. Together, PartitionKey and RowKey form the unique identifier for an entity.

Core Operations

The Azure Storage Table API provides a rich set of operations for managing your table data:

Table Operations

Operation	Description	HTTP Method	Endpoint
Create Table	Creates a new table in the storage account.	PUT	/tables
Query Tables	Queries for tables within the storage account.	GET	/tables
Delete Table	Deletes a specified table.	DELETE	/tables('{table_name}')

Entity Operations

Operation	Description	HTTP Method	Endpoint
Insert Entity	Inserts a new entity into a table.	POST	/{table_name}
Query Entities	Queries for entities within a table. Supports filtering and projection.	GET	/{table_name}
Update Entity	Updates an existing entity.	PUT	/{table_name}(PartitionKey='{pk}',RowKey='{rk}')
Merge Entity	Updates an existing entity by merging properties.	MERGE	/{table_name}(PartitionKey='{pk}',RowKey='{rk}')
Delete Entity	Deletes a specified entity.	DELETE	/{table_name}(PartitionKey='{pk}',RowKey='{rk}')
Insert or Replace Entity	Inserts an entity if it doesn't exist, otherwise replaces it.	PUT with Prefer: return-content-no-entity	/{table_name}(PartitionKey='{pk}',RowKey='{rk}')
Insert or Merge Entity	Inserts an entity if it doesn't exist, otherwise merges properties.	MERGE with Prefer: return-content-no-entity	/{table_name}(PartitionKey='{pk}',RowKey='{rk}')

Querying Entities

Querying entities is a fundamental part of using Table storage. You can specify filter expressions to retrieve specific entities. The query syntax is OData-like.

Filter Syntax Example:

PartitionKey eq 'Tasks' and Status eq 'Open' and Priority ge 5

Common Query Parameters:

• $filter: Specifies the filter expression.
• $select: Specifies which properties to return (projection).
• $top: Limits the number of entities returned.
• $orderby: Specifies the order of entities.

Data Types

Azure Table storage supports a variety of data types for properties, including:

• String
• Int32
• Int64
• Boolean
• DateTime
• Double
• Guid
• Binary (Byte Array)
• Geography/Geopoint (for geospatial queries)

Authentication and Authorization

Access to Azure Table storage is secured via Shared Key authentication or Azure Active Directory (Azure AD) integration. Ensure you follow best practices for managing access keys and permissions.

Further Reading

• Azure Table Storage Overview
• Table Service REST API Reference
• How to Use Azure Table Storage