stringqb/src/query_builder.rs

150 lines
3.3 KiB
Rust

//! QueryBuilder
//!
//! The QueryBuilder creates sql queries from chained methods
use std::any::Any;
use std::collections::HashMap;
use crate::drivers::DatabaseDriver;
#[derive(Debug)]
enum QueryClauseType {
AndGroupStart,
GroupEnd,
GroupStart,
Like,
OrGroupStart,
Where,
WhereIn,
}
#[derive(Debug)]
struct QueryClause {
clause_type: QueryClauseType,
conjunction: String,
string: String,
}
#[derive(Default, Debug)]
struct QueryState {
select_string: String,
from_string: String,
set_string: String,
order_string: String,
group_string: String,
// Keys for insert/update statement
set_array_keys: Vec<String>,
// Order by clause
order_array: HashMap<String, String>,
// Group by clause
group_array: HashMap<String, String>,
// Values to apply to prepared statements
values: Vec<Box<dyn Any>>,
// Values to apply to where clauses in prepared statements
where_values: Vec<Box<dyn Any>>,
limit: u32,
offset: u32,
// Query components for complex selects
query_map: Vec<QueryClause>,
// Query components for having clauses
having_map: Vec<QueryClause>,
}
impl QueryState {
pub fn new() -> QueryState {
QueryState::default()
}
}
/// The struct representing a query builder
#[derive(Default, Debug)]
pub struct QueryBuilder {
state: QueryState,
driver: Option<Box<dyn DatabaseDriver>>,
}
impl QueryBuilder {
/// Creates a new QueryBuilder instance
pub fn new() -> QueryBuilder {
QueryBuilder {
state: QueryState::new(),
driver: None,
}
}
/// Set the fields to select from the database
pub fn select(mut self, fields: &str) -> Self {
unimplemented!();
}
/// Set a key and value for an insert or update query
pub fn set(mut self, key: &str, value: Box<dyn Any>) -> Self {
// @TODO figure a way to make this easier to use
self.state.set_array_keys.push(key.to_string());
self.state.values.push(value);
self
}
/// Set a map of data for an insert or update query
pub fn set_batch(mut self, data: HashMap<String, Box<dyn Any>>) -> Self {
for (key, value) in data {
self = self.set(&key, value);
}
self
}
/// Specify the database table to select from
pub fn from(mut self, table_name: &str) -> Self {
// @TODO properly escape the table name
self.state.from_string = table_name.to_string();
self
}
/// Execute the built query
pub fn get(self) -> Box<dyn Any> {
unimplemented!();
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn set_key_value() {
let builder = QueryBuilder::new()
.set("foo", Box::new("bar"));
assert!(builder.state.values[0].is::<&str>());
}
// fn set_hashmap() {
// let qb = QueryBuilder::new();
//
// let mut authors = HashMap::new();
// authors.insert(
// String::from("Chinua Achebe"),
// Box::new("Nigeria"));
// authors.insert(
// String::from("Rabindranath Tagore"),
// Box::new("India"));
// authors.insert(
// String::from("Anita Nair"),
// Box::new("India"));
//
// let qb = qb.set_batch(authors);
//
// assert_eq!(qb.state.values.len(), 3);
// }
}