API Compatibility
This section describes APIs supported by GeminiDB DynamoDB-Compatible API.
Usage Notes
- You can add, delete, and modify tables of GeminiDB DynamoDB-Compatible instances only through DynamoDB APIs. Tables can only be read on the console.
- Tables created through non-DynamoDB APIs cannot be used on GeminiDB DynamoDB-Compatible instances.
- The current version does not support traffic statistics, traffic control, or transaction functions (TransactWriteItems and TransactGetItems).
- The current version does not support the following on-demand backup APIs: CreateBackup, DescribeBackup, DeleteBackup, ListBackups, and RestoreTableFromBackup.
- Hash or partition keys determine where items are stored in an internal storage device of a GeminiDB DynamoDB-Compatible instance. Amazon DynamoDB uses a dedicated hash function, while GeminiDB DynamoDB-Compatible API uses the Murmur3 algorithm. As a result, the sequence of data returned by a scan operation is different.
- The table or index name cannot contain periods (.).
- Due to different encoding methods, the size of each row of data in a table on a GeminiDB DynamoDB-Compatible instance is not strictly limited to 400 KB.
- All DDL APIs are synchronous APIs.
Supported Expressions
ConditionExpression of GeminiDB DynamoDB-Compatible API supports the following function syntax:
function ::=
attribute_exists (path)
| attribute_not_exists (path)
| attribute_type (path, type)
| begins_with (path, substr)
| contains (path, operand)
operand in contains(path,operand) can only be an attribute value (that is, the value placeholder).
UpdateExpression of GeminiDB DynamoDB-Compatible API supports the following syntax:
update-expression ::=
[ SET action [, action] ... ]
[ REMOVE action [, action] ...]
[ ADD action [, action] ... ]
[ DELETE action [, action] ...]
set-action ::=
path =value
value ::=
operand
| operand '+' operand
| operand '-' operand
operand ::=
path | function
function ::=
if_not_exists (path, value)
| list_append (list1, list2)
remove-action ::=
path
add-action ::=
path value
delete-action ::=
path value
In SET path = operand, operand cannot be set to path.
In SET path = operand1 '+'|'-' operand2, operand1 must be set to path, and operand2 must be an attribute value.
In SET path = if_not_exists (path, value), values of the two path parameters must be the same and must be expression attribute values.
All values can only be placeholders, for example, ':placeholder'.
Compatible APIs
|
API |
|---|
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
CreateTable |
Request parameter |
AttributeDefinitions |
Yes |
Yes |
- |
|
KeySchema |
Yes |
Yes |
- |
||
|
TableName |
Yes |
Yes |
Can contain 3 to 48 characters. The regular expression is ([\w-]+). |
||
|
BillingMode |
No |
No |
Billing parameter, which is not supported |
||
|
GlobalSecondaryIndexes |
No |
Yes |
- |
||
|
LocalSecondaryIndexes |
No |
Yes |
- |
||
|
ProvisionedThroughput |
Yes |
Yes |
- |
||
|
SSESpecification |
No |
No |
Not supported in the current version (planning). |
||
|
StreamSpecification |
No |
Yes |
- |
||
|
Tags |
No |
No |
Not supported in the current version (planning). |
||
|
Response parameter |
TableDescription |
- |
Yes |
- |
|
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
UpdateTable |
Request parameter |
AttributeDefinitions |
No |
Yes |
- |
|
BillingMode |
No |
No |
Billing parameter, which is not supported |
||
|
GlobalSecondaryIndexesUpdates |
Yes |
Yes |
CREATE and DELETE are supported, but UPDATE is not. |
||
|
ProvisionedThroughput |
No |
No |
Billing parameter, which is not supported |
||
|
ReplicaUpdates |
No |
No |
Default strong consistency |
||
|
SSESpecification |
No |
No |
Not supported in the current version (planning). |
||
|
StreamSpecification |
No |
Yes |
- |
||
|
TableName |
Yes |
Yes |
- |
||
|
Response parameter |
TableDescription |
- |
Yes |
- |
|
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
DescribeTable |
Request parameter |
TableName |
Yes |
Yes |
- |
|
Response parameter |
Table |
- |
Yes |
itemCount is not supported. |
|
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
ListTables |
Request parameter |
ExclusiveStartTableName |
No |
Yes |
- |
|
Limit |
No |
Yes |
- |
||
|
Response parameter |
LastEvaluatedTableName |
- |
Yes |
- |
|
|
TableNames |
- |
Yes |
- |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
DeleteTable |
Request parameter |
TableName |
Yes |
Yes |
- |
|
Response parameter |
TableDescription |
- |
Yes |
- |
|
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
PutItem |
Request parameter |
Item |
Yes |
Yes |
- |
|
TableName |
Yes |
Yes |
- |
||
|
ConditionalOperator |
No |
No |
Deprecated parameter. For details, see ConditionExpression. |
||
|
ConditionExpression |
No |
Yes |
- |
||
|
Expected |
No |
No |
Deprecated parameter. For details, see ConditionExpression. |
||
|
ExpressionAttributeNames |
No |
Yes |
- |
||
|
ExpressionAttributeValues |
No |
Yes |
- |
||
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
ReturnItemCollectionMetrics |
No |
No |
Statistics parameter, which is not supported |
||
|
ReturnValues |
No |
Yes |
- |
||
|
Response parameter |
Attributes |
- |
Yes |
- |
|
|
ConsumedCapacity |
- |
No |
Billing parameter, which is not supported |
||
|
ItemCollectionMetrics |
- |
No |
Statistics parameter, which is not supported |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
UpdateItem |
Request parameter |
Key |
Yes |
Yes |
- |
|
TableName |
Yes |
Yes |
- |
||
|
AttributeUpdates |
No |
No |
Deprecated parameter. For details, see UpdateExpression. |
||
|
ConditionalOperator |
No |
No |
Deprecated parameter. For details, see UpdateExpression. |
||
|
ConditionExpression |
No |
Yes |
- |
||
|
Expected |
No |
No |
Deprecated parameter. For details, see UpdateExpression. |
||
|
ExpressionAttributeNames |
No |
Yes |
- |
||
|
ExpressionAttributeValues |
No |
Yes |
- |
||
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
ReturnItemCollectionMetrics |
No |
No |
Statistics parameter, which is not supported |
||
|
ReturnValues |
No |
Yes |
- |
||
|
UpdateExpression |
No |
Yes |
- |
||
|
Response parameter |
Attributes |
- |
Yes |
- |
|
|
ConsumedCapacity |
- |
No |
Billing parameter, which is not supported |
||
|
ItemCollectionMetrics |
- |
No |
Statistics parameter, which is not supported |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
GetItem |
Request parameter |
Key |
Yes |
Yes |
- |
|
TableName |
Yes |
Yes |
- |
||
|
AttributesToGet |
No |
No |
Deprecated parameter. For details, see ProjectionExpression. |
||
|
ConsistentRead |
No |
No |
Default strong consistency |
||
|
ExpressionAttributeNames |
No |
Yes |
- |
||
|
ProjectionExpression |
No |
Yes |
- |
||
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
Response parameter |
ConsumedCapacity |
- |
No |
Billing parameter, which is not supported |
|
|
Item |
- |
Yes |
- |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
DeleteItem |
Request parameter |
Key |
Yes |
Yes |
- |
|
TableName |
Yes |
Yes |
- |
||
|
ConditionalOperator |
No |
No |
Deprecated parameter. For details, see ConditionExpression. |
||
|
ConditionExpression |
No |
Yes |
- |
||
|
Expected |
No |
No |
Deprecated parameter. For details, see ConditionExpression. |
||
|
ExpressionAttributeNames |
No |
Yes |
- |
||
|
ExpressionAttributeValues |
No |
Yes |
- |
||
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
ReturnItemCollectionMetrics |
No |
No |
Statistics parameter, which is not supported |
||
|
ReturnValues |
No |
Yes |
- |
||
|
Response parameter |
Attributes |
- |
Yes |
- |
|
|
ConsumedCapacity |
- |
No |
Billing parameter, which is not supported |
||
|
ItemCollectionMetrics |
- |
No |
Statistics parameter, which is not supported |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
BatchWriteItem |
Request parameter |
RequestItems |
Yes |
Yes |
- |
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
ReturnItemCollectionMetrics |
No |
No |
Statistics parameter, which is not supported |
||
|
Response parameter |
ConsumedCapacity |
- |
No |
Billing parameter, which is not supported |
|
|
ItemCollectionMetrics |
- |
No |
Statistics parameter, which is not supported |
||
|
UnprocessedItems |
- |
Yes |
- |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
BatchGetItem |
Request parameter |
RequestItems |
Yes |
Yes |
None |
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
Response parameter |
ConsumedCapacity |
- |
No |
Statistics parameter, which is not supported |
|
|
Responses |
- |
Yes |
- |
||
|
UnprocessedKeys |
- |
Yes |
- |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
Query |
Request parameter |
TableName |
Yes |
Yes |
- |
|
AttributesToGet |
No |
No |
Deprecated parameter. For details, see ProjectionExpression. |
||
|
ConditionalOperator |
No |
No |
Deprecated parameter. For details, see ProjectionExpression. |
||
|
ConsistentRead |
No |
No |
Default strong consistency |
||
|
ExclusiveStartKey |
No |
Yes |
- |
||
|
ExpressionAttributeNames |
No |
Yes |
- |
||
|
ExpressionAttributeValues |
No |
Yes |
- |
||
|
FilterExpression |
No |
Yes |
- |
||
|
IndexName |
No |
Yes |
- |
||
|
KeyConditionExpression |
No |
Yes |
- |
||
|
KeyConditions |
No |
No |
Deprecated parameter. For details, see KeyConditionExpression. |
||
|
Limit |
No |
Yes |
- |
||
|
ProjectionExpression |
No |
Yes |
- |
||
|
QueryFilter |
No |
No |
Deprecated parameter. For details, see FilterExpression. |
||
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
ScanIndexForward |
No |
Yes |
- |
||
|
Select |
No |
Yes |
COUNT is not supported. |
||
|
Response parameter |
ConsumedCapacity |
- |
No |
Billing parameter, which is not supported |
|
|
Count |
- |
Yes |
- |
||
|
Items |
- |
Yes |
- |
||
|
LastEvaluatedKey |
- |
Yes |
- |
||
|
ScannedCount |
- |
Yes |
- |
||
|
API |
Parameter |
Mandatory |
Supported |
Remarks |
|
|---|---|---|---|---|---|
|
Scan |
Request parameter |
TableName |
Yes |
Yes |
- |
|
AttributesToGet |
No |
No |
Deprecated parameter. For details, see ProjectionExpression. |
||
|
ConditionalOperator |
No |
No |
Deprecated parameter. For details, see ConditionExpression. |
||
|
ConsistentRead |
No |
No |
Default strong consistency |
||
|
ExclusiveStartKey |
No |
Yes |
- |
||
|
ExpressionAttributeNames |
No |
Yes |
- |
||
|
ExpressionAttributeValues |
No |
Yes |
- |
||
|
FilterExpression |
No |
Yes |
- |
||
|
IndexName |
No |
Yes |
- |
||
|
Limit |
No |
Yes |
- |
||
|
ProjectionExpression |
No |
Yes |
- |
||
|
ReturnConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
||
|
ScanFilter |
No |
No |
Deprecated parameter. For details, see FilterExpression. |
||
|
Segment |
No |
Yes |
- |
||
|
Select |
No |
Yes |
COUNT is not supported. |
||
|
TotalSegments |
No |
Yes |
- |
||
|
Response parameter |
ConsumedCapacity |
No |
No |
Billing parameter, which is not supported |
|
|
Count |
- |
Yes |
- |
||
|
Items |
- |
Yes |
- |
||
|
LastEvaluatedKey |
- |
Yes |
- |
||
|
ScannedCount |
- |
Yes |
- |
||
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