Naming conventions and data types

The following table describes naming conventions of tables and columns in Tablestore.

Item	Description
Structure	A name can contain uppercase letters (A to Z), lowercase letters (a to z), digits (0 to 9), and underscores (_).
First character	A name must start with an uppercase letter (A to Z), a lowercase letter (a to z), or an underscore (_).
Case sensitivity	A name is case-sensitive.
Length	A name can be 1 to 255 characters in length.
Uniqueness	A table name must be unique under the same instance. Table names under different Tablestore instances can be the same.

The following table describes data types of values in primary key columns.

Data type	Description	Size limit
String	Data is in UTF-8. Empty strings are allowed.	Up to 1 KB
Integer	Data is 64-bit long.	Up to 8 Bytes
Binary	Data is binary. Empty values are allowed.	Up to 1 KB

The following table describes data types of values in attribute columns.

Data type	Description	Size limit
String	Data is in UTF-8. Empty strings are allowed.	For more information, see Limits.
Integer	Data is 64-bit long.	Up to 8 Bytes
Double	Data is 64-bit long.	Up to 8 Bytes
Boolean	The value can be True or False.	Up to 1 Byte
Binary	Data is binary. Empty values are allowed.	For more information, see Limits.