class Aws::DynamoDB::Types::QueryInput

Represents the input of a `Query` operation.

@note When making an API call, you may pass QueryInput

data as a hash:

    {
      table_name: "TableName", # required
      index_name: "IndexName",
      select: "ALL_ATTRIBUTES", # accepts ALL_ATTRIBUTES, ALL_PROJECTED_ATTRIBUTES, SPECIFIC_ATTRIBUTES, COUNT
      attributes_to_get: ["AttributeName"],
      limit: 1,
      consistent_read: false,
      key_conditions: {
        "AttributeName" => {
          attribute_value_list: ["value"], # value <Hash,Array,String,Numeric,Boolean,IO,Set,nil>
          comparison_operator: "EQ", # required, accepts EQ, NE, IN, LE, LT, GE, GT, BETWEEN, NOT_NULL, NULL, CONTAINS, NOT_CONTAINS, BEGINS_WITH
        },
      },
      query_filter: {
        "AttributeName" => {
          attribute_value_list: ["value"], # value <Hash,Array,String,Numeric,Boolean,IO,Set,nil>
          comparison_operator: "EQ", # required, accepts EQ, NE, IN, LE, LT, GE, GT, BETWEEN, NOT_NULL, NULL, CONTAINS, NOT_CONTAINS, BEGINS_WITH
        },
      },
      conditional_operator: "AND", # accepts AND, OR
      scan_index_forward: false,
      exclusive_start_key: {
        "AttributeName" => "value", # value <Hash,Array,String,Numeric,Boolean,IO,Set,nil>
      },
      return_consumed_capacity: "INDEXES", # accepts INDEXES, TOTAL, NONE
      projection_expression: "ProjectionExpression",
      filter_expression: "ConditionExpression",
      key_condition_expression: "KeyExpression",
      expression_attribute_names: {
        "ExpressionAttributeNameVariable" => "AttributeName",
      },
      expression_attribute_values: {
        "ExpressionAttributeValueVariable" => "value", # value <Hash,Array,String,Numeric,Boolean,IO,Set,nil>
      },
    }

@!attribute [rw] table_name

The name of the table containing the requested items.
@return [String]

@!attribute [rw] index_name

The name of an index to query. This index can be any local secondary
index or global secondary index on the table. Note that if you use
the `IndexName` parameter, you must also provide `TableName.`
@return [String]

@!attribute [rw] select

The attributes to be returned in the result. You can retrieve all
item attributes, specific item attributes, the count of matching
items, or in the case of an index, some or all of the attributes
projected into the index.

* `ALL_ATTRIBUTES` - Returns all of the item attributes from the
  specified table or index. If you query a local secondary index,
  then for each matching item in the index, DynamoDB fetches the
  entire item from the parent table. If the index is configured to
  project all item attributes, then all of the data can be obtained
  from the local secondary index, and no fetching is required.

* `ALL_PROJECTED_ATTRIBUTES` - Allowed only when querying an index.
  Retrieves all attributes that have been projected into the index.
  If the index is configured to project all attributes, this return
  value is equivalent to specifying `ALL_ATTRIBUTES`.

* `COUNT` - Returns the number of matching items, rather than the
  matching items themselves.

* `SPECIFIC_ATTRIBUTES` - Returns only the attributes listed in
  `AttributesToGet`. This return value is equivalent to specifying
  `AttributesToGet` without specifying any value for `Select`.

  If you query or scan a local secondary index and request only
  attributes that are projected into that index, the operation will
  read only the index and not the table. If any of the requested
  attributes are not projected into the local secondary index,
  DynamoDB fetches each of these attributes from the parent table.
  This extra fetching incurs additional throughput cost and latency.

  If you query or scan a global secondary index, you can only
  request attributes that are projected into the index. Global
  secondary index queries cannot fetch attributes from the parent
  table.

If neither `Select` nor `AttributesToGet` are specified, DynamoDB
defaults to `ALL_ATTRIBUTES` when accessing a table, and
`ALL_PROJECTED_ATTRIBUTES` when accessing an index. You cannot use
both `Select` and `AttributesToGet` together in a single request,
unless the value for `Select` is `SPECIFIC_ATTRIBUTES`. (This usage
is equivalent to specifying `AttributesToGet` without any value for
`Select`.)

<note markdown="1"> If you use the `ProjectionExpression` parameter, then the value for
`Select` can only be `SPECIFIC_ATTRIBUTES`. Any other value for
`Select` will return an error.

 </note>
@return [String]

@!attribute [rw] attributes_to_get

This is a legacy parameter. Use `ProjectionExpression` instead. For
more information, see [AttributesToGet][1] in the *Amazon DynamoDB
Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.AttributesToGet.html
@return [Array<String>]

@!attribute [rw] limit

The maximum number of items to evaluate (not necessarily the number
of matching items). If DynamoDB processes the number of items up to
the limit while processing the results, it stops the operation and
returns the matching values up to that point, and a key in
`LastEvaluatedKey` to apply in a subsequent operation, so that you
can pick up where you left off. Also, if the processed dataset size
exceeds 1 MB before DynamoDB reaches this limit, it stops the
operation and returns the matching values up to the limit, and a key
in `LastEvaluatedKey` to apply in a subsequent operation to continue
the operation. For more information, see [Query and Scan][1] in the
*Amazon DynamoDB Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/QueryAndScan.html
@return [Integer]

@!attribute [rw] consistent_read

Determines the read consistency model: If set to `true`, then the
operation uses strongly consistent reads; otherwise, the operation
uses eventually consistent reads.

Strongly consistent reads are not supported on global secondary
indexes. If you query a global secondary index with `ConsistentRead`
set to `true`, you will receive a `ValidationException`.
@return [Boolean]

@!attribute [rw] key_conditions

This is a legacy parameter. Use `KeyConditionExpression` instead.
For more information, see [KeyConditions][1] in the *Amazon DynamoDB
Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.KeyConditions.html
@return [Hash<String,Types::Condition>]

@!attribute [rw] query_filter

This is a legacy parameter. Use `FilterExpression` instead. For more
information, see [QueryFilter][1] in the *Amazon DynamoDB Developer
Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.QueryFilter.html
@return [Hash<String,Types::Condition>]

@!attribute [rw] conditional_operator

This is a legacy parameter. Use `FilterExpression` instead. For more
information, see [ConditionalOperator][1] in the *Amazon DynamoDB
Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/LegacyConditionalParameters.ConditionalOperator.html
@return [String]

@!attribute [rw] scan_index_forward

Specifies the order for index traversal: If `true` (default), the
traversal is performed in ascending order; if `false`, the traversal
is performed in descending order.

Items with the same partition key value are stored in sorted order
by sort key. If the sort key data type is Number, the results are
stored in numeric order. For type String, the results are stored in
order of UTF-8 bytes. For type Binary, DynamoDB treats each byte of
the binary data as unsigned.

If `ScanIndexForward` is `true`, DynamoDB returns the results in the
order in which they are stored (by sort key value). This is the
default behavior. If `ScanIndexForward` is `false`, DynamoDB reads
the results in reverse order by sort key value, and then returns the
results to the client.
@return [Boolean]

@!attribute [rw] exclusive_start_key

The primary key of the first item that this operation will evaluate.
Use the value that was returned for `LastEvaluatedKey` in the
previous operation.

The data type for `ExclusiveStartKey` must be String, Number, or
Binary. No set data types are allowed.
@return [Hash<String,Types::AttributeValue>]

@!attribute [rw] return_consumed_capacity

Determines the level of detail about provisioned throughput
consumption that is returned in the response:

* `INDEXES` - The response includes the aggregate `ConsumedCapacity`
  for the operation, together with `ConsumedCapacity` for each table
  and secondary index that was accessed.

  Note that some operations, such as `GetItem` and `BatchGetItem`,
  do not access any indexes at all. In these cases, specifying
  `INDEXES` will only return `ConsumedCapacity` information for
  table(s).

* `TOTAL` - The response includes only the aggregate
  `ConsumedCapacity` for the operation.

* `NONE` - No `ConsumedCapacity` details are included in the
  response.
@return [String]

@!attribute [rw] projection_expression

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][1] in the
*Amazon DynamoDB Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html
@return [String]

@!attribute [rw] filter_expression

A string that contains conditions that DynamoDB applies after the
`Query` operation, but before the data is returned to you. Items
that do not satisfy the `FilterExpression` criteria are not
returned.

A `FilterExpression` does not allow key attributes. You cannot
define a filter expression based on a partition key or a sort key.

<note markdown="1"> A `FilterExpression` is applied after the items have already been
read; the process of filtering does not consume any additional read
capacity units.

 </note>

For more information, see [Filter Expressions][1] in the *Amazon
DynamoDB Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/QueryAndScan.html#FilteringResults
@return [String]

@!attribute [rw] key_condition_expression

The condition that specifies the key values for items to be
retrieved by the `Query` action.

The condition must perform an equality test on a single partition
key value.

The condition can optionally perform one of several comparison tests
on a single sort key value. This allows `Query` to retrieve one item
with a given partition key value and sort key value, or several
items that have the same partition key value but different sort key
values.

The partition key equality test is required, and must be specified
in the following format:

`partitionKeyName` *=* `:partitionkeyval`

If you also want to provide a condition for the sort key, it must be
combined using `AND` with the condition for the sort key. Following
is an example, using the **=** comparison operator for the sort key:

`partitionKeyName` `=` `:partitionkeyval` `AND` `sortKeyName` `=`
`:sortkeyval`

Valid comparisons for the sort key condition are as follows:

* `sortKeyName` `=` `:sortkeyval` - true if the sort key value is
  equal to `:sortkeyval`.

* `sortKeyName` `<` `:sortkeyval` - true if the sort key value is
  less than `:sortkeyval`.

* `sortKeyName` `<=` `:sortkeyval` - true if the sort key value is
  less than or equal to `:sortkeyval`.

* `sortKeyName` `>` `:sortkeyval` - true if the sort key value is
  greater than `:sortkeyval`.

* `sortKeyName` `>= ` `:sortkeyval` - true if the sort key value is
  greater than or equal to `:sortkeyval`.

* `sortKeyName` `BETWEEN` `:sortkeyval1` `AND` `:sortkeyval2` - true
  if the sort key value is greater than or equal to `:sortkeyval1`,
  and less than or equal to `:sortkeyval2`.

* `begins_with (` `sortKeyName`, `:sortkeyval` `)` - true if the
  sort key value begins with a particular operand. (You cannot use
  this function with a sort key that is of type Number.) Note that
  the function name `begins_with` is case-sensitive.

Use the `ExpressionAttributeValues` parameter to replace tokens such
as `:partitionval` and `:sortval` with actual values at runtime.

You can optionally use the `ExpressionAttributeNames` parameter to
replace the names of the partition key and sort key with placeholder
tokens. This option might be necessary if an attribute name
conflicts with a DynamoDB reserved word. For example, the following
`KeyConditionExpression` parameter causes an error because *Size* is
a reserved word:

* `Size = :myval`

^

To work around this, define a placeholder (such a `#S`) to represent
the attribute name *Size*. `KeyConditionExpression` then is as
follows:

* `#S = :myval`

^

For a list of reserved words, see [Reserved Words][1] in the *Amazon
DynamoDB Developer Guide*.

For more information on `ExpressionAttributeNames` and
`ExpressionAttributeValues`, see [Using Placeholders for Attribute
Names and Values][2] in the *Amazon DynamoDB Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html
[2]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ExpressionPlaceholders.html
@return [String]

@!attribute [rw] expression_attribute_names

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][1] 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`

^

<note markdown="1"> Tokens that begin with the **\:** character are *expression
attribute values*, which are placeholders for the actual value at
runtime.

 </note>

For more information on expression attribute names, see [Specifying
Item Attributes][2] in the *Amazon DynamoDB Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ReservedWords.html
[2]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.AccessingItemAttributes.html
@return [Hash<String,String>]

@!attribute [rw] expression_attribute_values

One or more values that can be substituted in an expression.

Use the **\:** (colon) character in an expression to dereference an
attribute value. For example, suppose that you wanted to check
whether the value of the *ProductStatus* attribute was one of the
following:

`Available | Backordered | Discontinued`

You would first need to specify `ExpressionAttributeValues` as
follows:

`\{ ":avail":\{"S":"Available"\}, ":back":\{"S":"Backordered"\},
":disc":\{"S":"Discontinued"\} \}`

You could then use these values in an expression, such as this:

`ProductStatus IN (:avail, :back, :disc)`

For more information on expression attribute values, see [Specifying
Conditions][1] in the *Amazon DynamoDB Developer Guide*.

[1]: https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Expressions.SpecifyingConditions.html
@return [Hash<String,Types::AttributeValue>]

@see docs.aws.amazon.com/goto/WebAPI/dynamodb-2012-08-10/QueryInput AWS API Documentation

Constants

SENSITIVE