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Mapping results into Rust structures

TODO: provide more details and link to examples

In ordert to query information from Cassandra DB and transform results to Rust types an structures each row in a query result should be transformed leveraging one of following traits provided by CDRS cdrs::types::{AsRustType, AsRust, IntoRustByName, ByName, IntoRustByIndex, ByIndex}.

  • AsRustType may be used in order to transform such complex structures as Cassandra lists, sets, tuples. The Cassandra value in this case could non-set and null values.

  • AsRust trait may be used for similar purposes as AsRustType but it assumes that Cassandra value is neither non-set nor null value. Otherwise it panics.

  • IntoRustByName trait may be used to access a value as a Rust structure/type by name. Such as in case of rows where each column has its own name, and maps. These values may be as well non-set and null.

  • ByName trait is the same as IntoRustByName but value should be neither non-set nor null. Otherwise it panics.

  • IntoRustByIndex is the same as IntoRustByName but values could be accessed via column index basing on their order provided in query. These values may be as well non-set and null.

  • ByIndex is the same as IntoRustByIndex but value can be neither non-set nor null. Otherwise it panics.

Relations between Cassandra and Rust types are described in type-mapping.md. For details see examples.