[−][src]Crate indexer
Json Indexer
multi value indexer for a json objects.
this crate allows to create a sorted map of json objects based on the dot path, its similar to what a database like mongodb will generate and index based on the path given, this crate is meant to be used in create no sql database. this crate was created to be used as indexing structure for escanordb.
Example
Single index
This example demonstrates how you can use json indexer to index a json value
use indexer::{Indexer, IndexString, Index, IndexOrd, BatchTransaction}; use serde_json::Value; let string_indexer = Indexer::String(IndexString { ordering: IndexOrd::ASC }); let mut names_index = Index::new(string_indexer); names_index.batch(|b| { b.insert("user.1".to_owned(), Value::String("Kwadwo".to_string())); b.insert("user.2".to_owned(), Value::String("Kwame".to_string())); b.insert("user.3".to_owned(), Value::String("Joseph".to_string())); b.insert("user.4".to_owned(), Value::String("Jake".to_string())); b.insert("user.5".to_owned(), Value::String("Mambisi".to_string())); b.insert("user.6".to_owned(), Value::String("Ama".to_string())); b.commit() }); println!("{:?}", names_index.read()); /*outputs { "user.6": String("Ama"), "user.4": String("Jake"), "user.3": String("Joseph"), "user.1": String("Kwadwo"), "user.2": String("Kwame"), "user.5": String("Mambisi") } */ let res = names_index.find_all("*", "like", Value::String("k*".to_string())); println!("users whose name starts with K: {:?}", res.read()); /*outputs users whose name starts with K: {"user.8": String("Kwadwo"), "user.1": String("Kwadwo"), "user.2": String("Kwame")} */
Multi index with dot path
This example demonstrates how you can use json indexer to index a full json object using multiple dot paths
use std::collections::HashMap; use indexer::{JsonPathOrder, IndexOrd, Indexer, IndexJson, Index, BatchTransaction}; use serde_json::Value; let mut students: HashMap<String, Student> = HashMap::new(); students.insert("student:0".to_owned(), Student { name: "Mambisi".to_owned(), age: 21, state : "CA".to_owned(), gpa: 3.1, }); students.insert("student:1".to_owned(), Student { name: "Joseph".to_owned(), age: 12, state : "CA".to_owned(), gpa: 3.1, }); students.insert("student:2".to_owned(), Student { name: "Elka".to_owned(), age: 12, state : "FL".to_owned(), gpa: 4.0, }); students.insert("student:18".to_owned(), Student { name: "Alex".to_owned(), age: 15, state : "NY".to_owned(), gpa: 3.7, }); students.insert("student:18".to_owned(), Student { name: "Jackson".to_owned(), age: 17, state : "NY".to_owned(), gpa: 3.8, }); let gpa_order = JsonPathOrder { path: "gpa".to_string(), ordering: IndexOrd::DESC, }; let name_order = JsonPathOrder { path: "name".to_string(), ordering: IndexOrd::ASC, }; let state_order = JsonPathOrder { path: "state".to_string(), ordering: IndexOrd::ASC, }; let indexer = Indexer::Json(IndexJson { path_orders: vec![name_order, gpa_order, state_order] }); let mut students_index = Index::new(indexer); students_index.batch(|b| { &students.iter().for_each(|(k, v)| { let json = serde_json::to_value(v).unwrap_or(Value::Null); b.insert(k.to_owned(), json); }); b.commit() }); println!("{:?}", index.read()); /* Outputs { "student:2": Object({"age": Number(12), "gpa": Number(4.0), "name": String("Elka"), "state": String("FL")}), "student:18": Object({"age": Number(17), "gpa": Number(3.8), "name": String("Jackson"), "state": String("NY")}), "student:1": Object({"age": Number(12), "gpa": Number(3.1), "name": String("Joseph"), "state": String("CA")}), "student:0": Object({"age": Number(21), "gpa": Number(3.1), "name": String("Mambisi"), "state": String("CA")}) } */ // Querying an index let query = students_index.find_all("state", "eq", Value::String("CA".to_string())); println!("Find all students in CA: {:?}", query.read()); /* Find all students in CA: { "student:1": Object({"age": Number(12), "gpa": Number(3.1), "name": String("Joseph"), "state": String("CA")}), "student:0": Object({"age": Number(21), "gpa": Number(3.1), "name": String("Mambisi"), "state": String("CA")}) } */ let query = students_index.find_all("gpa", "gt", Value::from(3.5)); println!("Find all students whose gpa greater than 3.5: {:?}", query.read()); /* Find all students whose gpa greater than 3.5: { "student:2": Object({"age": Number(12), "gpa": Number(4.0), "name": String("Elka"), "state": String("FL")}), "student:18": Object({"age": Number(17), "gpa": Number(3.8), "name": String("Jackson"), "state": String("NY")}) } */
Structs
Batch | |
Index | |
IndexFloat | |
IndexInt | |
IndexJson | |
IndexString | |
JsonPathOrder |
Enums
IndexOrd | |
Indexer | |
QueryOperator |
Traits
BatchTransaction |