Use auto-increment primary key columns - Tablestore SDK for Python - Tablestore

Use Tablestore SDK for Python to configure an auto-increment primary key column and obtain its generated value when you write data.

Prerequisites

Install the Tablestore SDK for Python and initialize a client. Auto-increment primary key columns require version 4.0.0 or later. We recommend that you use the latest version.

Function description

Tablestore generates a signed 64-bit integer for an auto-increment primary key column. Generated values are unique and strictly increasing within the same partition key but may not be consecutive.

Configure an auto-increment primary key column

When you create a table, set a non-partition primary key column of the INTEGER type to PK_AUTO_INCR. Each table can have at most one auto-increment primary key column. You cannot add one after the table is created.

The following example creates example_table with the partition key id and the auto-increment primary key column sequence_id.

table_meta = TableMeta(
    "example_table",
    [
        ("id", "STRING"),
        ("sequence_id", "INTEGER", PK_AUTO_INCR),
    ],
)
table_options = TableOptions()
reserved_throughput = ReservedThroughput(CapacityUnit(0, 0))

client.create_table(table_meta, table_options, reserved_throughput)

Write data and obtain the generated value

When you write data, set the value of the auto-increment primary key column to PK_AUTO_INCR. To use the generated value in subsequent queries or updates, set return_type to ReturnType.RT_PK.

primary_key = [
    ("id", "device-001"),
    ("sequence_id", PK_AUTO_INCR),
]
attribute_columns = [("status", "online")]
row = Row(primary_key, attribute_columns)

_, return_row = client.put_row(
    "example_table",
    row,
    return_type=ReturnType.RT_PK,
)

print(return_row.primary_key)

Parameters

Auto-increment primary key column configuration

The tuple in schema_of_primary_key[] that configures an auto-increment primary key column contains the following elements.

Name	Type	Description
name (required)	`str`	The name of the primary key column.
type (required)	`str`	The type of the primary key column. Set the value to `INTEGER`.
option (required)	`PrimaryKeyOption`	The primary key option. Set the value to `PK_AUTO_INCR`. An auto-increment primary key column cannot be the partition key.

Write parameters

The put_row method contains the following parameters that are related to auto-increment primary key columns.

Name	Type	Description
table_name (required)	`str`	The name of the table.
row (required)	`Row`	The row to write. Set the value of the auto-increment primary key column to `PK_AUTO_INCR`.
return_type (optional)	`ReturnType`	The response type. Set the value to `RT_PK` to return the primary key of the written row. If you do not specify this parameter, the primary key is not returned.

Response

The put_row method returns a tuple that contains the following information.

Field	Type	Description
consumed	`CapacityUnit`	The read and write CUs consumed by the operation.
return_row	`Row`	If `return_type` is set to `RT_PK`, this field contains the complete primary key generated by Tablestore. Otherwise, the value is `None`.