Struct rusoto_dynamodb::BatchGetItemInput [−][src]
pub struct BatchGetItemInput { pub request_items: HashMap<String, KeysAndAttributes>, pub return_consumed_capacity: Option<String>, }
Represents the input of a BatchGetItem
operation.
Fields
request_items: HashMap<String, KeysAndAttributes>
A map of one or more table names and, for each table, a map that describes one or more items to retrieve from that table. Each table name can be used only once per BatchGetItem
request.
Each element in the map of items to retrieve consists of the following:
-
ConsistentRead
- Iftrue
, a strongly consistent read is used; iffalse
(the default), an eventually consistent read is used. -
ExpressionAttributeNames
- One or more substitution tokens for attribute names in theProjectionExpression
parameter. The following are some use cases for usingExpressionAttributeNames
:-
To access an attribute whose name conflicts with a DynamoDB reserved word.
-
To create a placeholder for repeating occurrences of an attribute name in an expression.
-
To prevent special characters in an attribute name from being misinterpreted in an expression.
Use the # character in an expression to dereference an attribute name. For example, consider the following attribute name:
-
Percentile
The name of this attribute conflicts with a reserved word, so it cannot be used directly in an expression. (For the complete list of reserved words, see Reserved Words in the Amazon DynamoDB Developer Guide). To work around this, you could specify the following for
ExpressionAttributeNames
:-
{"#P":"Percentile"}
You could then use this substitution in an expression, as in this example:
-
#P = :val
Tokens that begin with the : character are expression attribute values, which are placeholders for the actual value at runtime.
For more information on expression attribute names, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
-
-
Keys
- An array of primary key attribute values that define specific items in the table. For each primary key, you must provide all of the key attributes. For example, with a simple primary key, you only need to provide the partition key value. For a composite key, you must provide both the partition key value and the sort key value. -
ProjectionExpression
- A string that identifies one or more attributes to retrieve from the table. These attributes can include scalars, sets, or elements of a JSON document. The attributes in the expression must be separated by commas.If no attribute names are specified, then all attributes will be returned. If any of the requested attributes are not found, they will not appear in the result.
For more information, see Accessing Item Attributes in the Amazon DynamoDB Developer Guide.
-
AttributesToGet
- This is a legacy parameter. UseProjectionExpression
instead. For more information, see AttributesToGet in the Amazon DynamoDB Developer Guide.
return_consumed_capacity: Option<String>
Trait Implementations
impl Default for BatchGetItemInput
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impl Default for BatchGetItemInput
fn default() -> BatchGetItemInput
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fn default() -> BatchGetItemInput
Returns the "default value" for a type. Read more
impl Debug for BatchGetItemInput
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impl Debug for BatchGetItemInput
fn fmt(&self, f: &mut Formatter) -> Result
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fn fmt(&self, f: &mut Formatter) -> Result
Formats the value using the given formatter. Read more
impl Clone for BatchGetItemInput
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impl Clone for BatchGetItemInput
fn clone(&self) -> BatchGetItemInput
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fn clone(&self) -> BatchGetItemInput
Returns a copy of the value. Read more
fn clone_from(&mut self, source: &Self)
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fn clone_from(&mut self, source: &Self)
Performs copy-assignment from source
. Read more
impl PartialEq for BatchGetItemInput
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impl PartialEq for BatchGetItemInput
fn eq(&self, other: &BatchGetItemInput) -> bool
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fn eq(&self, other: &BatchGetItemInput) -> bool
This method tests for self
and other
values to be equal, and is used by ==
. Read more
fn ne(&self, other: &BatchGetItemInput) -> bool
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fn ne(&self, other: &BatchGetItemInput) -> bool
This method tests for !=
.
Auto Trait Implementations
impl Send for BatchGetItemInput
impl Send for BatchGetItemInput
impl Sync for BatchGetItemInput
impl Sync for BatchGetItemInput