Struct aws_sdk_dynamodb::types::KeysAndAttributes

#[non_exhaustive]
pub struct KeysAndAttributes {
    pub keys: Vec<HashMap<String, AttributeValue>>,
    pub attributes_to_get: Option<Vec<String>>,
    pub consistent_read: Option<bool>,
    pub projection_expression: Option<String>,
    pub expression_attribute_names: Option<HashMap<String, String>>,
}

Represents a set of primary keys and, for each key, the attributes to retrieve from 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. For a composite primary key, you must provide both the partition key and the sort key.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

keys: Vec<HashMap<String, AttributeValue>>

The primary key attribute values that define the items and the attributes associated with the items.

attributes_to_get: Option<Vec<String>>

This is a legacy parameter. Use ProjectionExpression instead. For more information, see Legacy Conditional Parameters in the Amazon DynamoDB Developer Guide.

consistent_read: Option<bool>

The consistency of a read operation. If set to true, then a strongly consistent read is used; otherwise, an eventually consistent read is used.

projection_expression: Option<String>

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 ProjectionExpression 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.

expression_attribute_names: Option<HashMap<String, String>>

One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:

• 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.

Implementations

impl KeysAndAttributes

pub fn keys(&self) -> &[HashMap<String, AttributeValue>]

The primary key attribute values that define the items and the attributes associated with the items.

pub fn attributes_to_get(&self) -> &[String]

This is a legacy parameter. Use ProjectionExpression instead. For more information, see Legacy Conditional Parameters in the Amazon DynamoDB Developer Guide.

If no value was sent for this field, a default will be set. If you want to determine if no value was sent, use .attributes_to_get.is_none().

pub fn consistent_read(&self) -> Option<bool>

The consistency of a read operation. If set to true, then a strongly consistent read is used; otherwise, an eventually consistent read is used.

pub fn projection_expression(&self) -> Option<&str>

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 ProjectionExpression 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.

pub fn expression_attribute_names(&self) -> Option<&HashMap<String, String>>

One or more substitution tokens for attribute names in an expression. The following are some use cases for using ExpressionAttributeNames:

• 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.

impl KeysAndAttributes

pub fn builder() -> KeysAndAttributesBuilder

Creates a new builder-style object to manufacture KeysAndAttributes.

Trait Implementations

impl Clone for KeysAndAttributes

fn clone(&self) -> KeysAndAttributes

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for KeysAndAttributes

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl PartialEq for KeysAndAttributes

fn eq(&self, other: &KeysAndAttributes) -> bool

This method tests for self and other values to be equal, and is used by ==.

fn ne(&self, other: &Rhs) -> bool

This method tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl StructuralPartialEq for KeysAndAttributes