Query Compiler

The heart of Ryx — transforms Python query expressions into optimized SQL.

Pipeline

Python QuerySet methods
    │
    ▼
QueryNode (Rust AST)
    │
    ▼
compiler::compile()
    │
    ▼
CompiledQuery { sql: String, values: Vec<SqlValue> }

AST Types

QueryNode

The root of every query:

pub struct QueryNode {
    pub operation: QueryOperation,  // Select, Aggregate, Count, Delete, Update, Insert
    pub table: String,
    pub columns: Vec<String>,
    pub filters: Vec<FilterNode>,
    pub q_tree: Option<QNode>,
    pub joins: Vec<JoinClause>,
    pub group_by: Vec<String>,
    pub having: Vec<FilterNode>,
    pub order_by: Vec<OrderByClause>,
    pub limit: Option<u64>,
    pub offset: Option<u64>,
    pub distinct: bool,
}

QNode — Boolean Expression Tree

pub enum QNode {
    Leaf { field: String, lookup: String, value: SqlValue, negated: bool },
    And { left: Box<QNode>, right: Box<QNode> },
    Or  { left: Box<QNode>, right: Box<QNode> },
    Not { inner: Box<QNode> },
}

SqlValue — Type-Safe Values

pub enum SqlValue {
    Null,
    Bool(bool),
    Int(i64),
    Float(f64),
    Text(String),
    Bytes(Vec<u8>),
    Date(chrono::NaiveDate),
    Time(chrono::NaiveTime),
    DateTime(chrono::NaiveDateTime),
    Json(serde_json::Value),
}

JoinClause

pub enum JoinKind { Inner, LeftOuter, RightOuter, FullOuter, Cross }

pub struct JoinClause {
    pub table: String,
    pub condition: String,
    pub kind: JoinKind,
    pub alias: Option<String>,
}

Compilation Process

1. SELECT clause — columns or *
2. FROM clause — table
3. JOINs — Each JoinClause rendered with proper kind
4. WHERE — Flat filters AND-ed, then Q-tree recursively compiled
5. GROUP BY — If group_by is non-empty
6. HAVING — If having is non-empty
7. ORDER BY — Each OrderByClause with ASC/DESC
8. LIMIT/OFFSET — If set
9. DISTINCT — If flag is true

Q-Tree Compilation

The Q-tree is compiled recursively:

Q(active=True) | Q(views__gte=1000)

QNode::Or {
    left:  Leaf { field: "active", lookup: "exact", value: Bool(true) }
    right: Leaf { field: "views", lookup: "gte", value: Int(1000) }
}

→ ("active" = ? OR "views" >= ?)

Nested expressions:

(Q(active=True) & Q(views__gte=100)) | Q(featured=True)

→ (("active" = ? AND "views" >= ?) OR "featured" = ?)

Lookup Compilation

Each lookup generates SQL differently:

match lookup.as_str() {
    "exact"     => format!("{col} = ?"),
    "gt"        => format!("{col} > ?"),
    "contains"  => { values.push(wrap_percent(value)); format!("{col} LIKE ?") }
    "isnull"    => if value { format!("{col} IS NULL") } else { format!("{col} IS NOT NULL") }
    "in"        => { let placeholders = expand_placeholders(values.len()); format!("{col} IN ({placeholders})") }
    "range"     => format!("{col} BETWEEN ? AND ?"),
    custom      => template.replace("{col}", &col),  // Custom lookup
}

Identifier Quoting

All identifiers are quoted for safety:

fn quote_ident(name: &str) -> String {
    format!("\"{}\"", name)
}
// "posts", "author_id", "created_at"

Output

pub struct CompiledQuery {
    pub sql: String,
    pub values: Vec<SqlValue>,
}

This is passed directly to sqlx::query(&sql).bind(values).fetch_all(pool).

Next Steps

→ Connection Pool — Pool management