mool 0.2.0

A source-first Rust database toolkit for typed SQL queries, migrations, and model metadata
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137

//! Dialect-aware SQL rendering, planning, and validation engine.
use indexmap::IndexMap;
use std::any::type_name;
use std::collections::{HashMap, HashSet};

use crate::argvalue::ArgValue;
use crate::interfaces::Record;
use crate::placeholders::Dialect;
use crate::relations::ReferenceMeta;

use super::dialect::{self, DialectRenderer};
use super::handles::VarId;
use super::plan::ParamSpec;
use super::source::Source;
use super::validate::{
    singular_alias, source_alias, source_key, validate_identifier, validate_reference,
    validate_source_shape,
};
use crate::QueryError;

mod expr;
mod params;
mod projection;
mod sources;
mod statements;
mod write;

#[derive(Clone)]
pub(super) struct SelectModel {
    pub(super) source: Source,
    pub(super) root_alias: String,
    pub(super) scan_root_alias: String,
    pub(super) references: IndexMap<String, ReferenceMeta>,
    pub(super) columns: Vec<String>,
    pub(super) result_type: &'static str,
}

#[derive(Clone, Copy)]
pub(super) enum RenderMode<'a> {
    Select(&'a SelectModel),
    MutationRoot { source: &'a Source },
}

impl SelectModel {
    pub(super) fn new<T>(source: &Source) -> Result<Self, QueryError>
    where
        T: Record,
    {
        validate_source_shape::<T>(source)?;
        let schema = T::record_schema();
        let scan_root_alias = match schema.root_name {
            Some(root_name) => root_name.to_string(),
            None => singular_alias(schema.table_name),
        };
        validate_identifier(&scan_root_alias)?;
        let root_alias = source_alias(source, &scan_root_alias);
        validate_identifier(&root_alias)?;
        let references = schema
            .references
            .into_iter()
            .map(|reference| {
                validate_reference(&reference)?;
                Ok((reference.logical_name.to_string(), reference))
            })
            .collect::<Result<IndexMap<_, _>, QueryError>>()?;
        Ok(Self {
            source: source.clone(),
            root_alias,
            scan_root_alias,
            references,
            columns: schema.column_names,
            result_type: type_name::<T>(),
        })
    }

    /// Builds a projection-free model over a source for aggregate terminals
    /// (`count`, `scalar`, `exists`). Only root-table columns are addressable;
    /// joined references require a row-shaped `Record` projection instead.
    pub(super) fn source_only(source: &Source) -> Result<Self, QueryError> {
        let scan_root_alias = singular_alias(source_key(source).2);
        validate_identifier(&scan_root_alias)?;
        let root_alias = source_alias(source, &scan_root_alias);
        validate_identifier(&root_alias)?;
        Ok(Self {
            source: source.clone(),
            root_alias,
            scan_root_alias,
            references: IndexMap::new(),
            columns: Vec::new(),
            result_type: "",
        })
    }
}

pub(super) struct Renderer {
    dialect: Dialect,
    dialect_renderer: &'static dyn DialectRenderer,
    params: IndexMap<String, PlannedParam>,
    bind_order: Vec<String>,
    var_names: HashMap<VarId, String>,
    named_vars: HashSet<String>,
    var_counter: usize,
    value_counter: usize,
    prebound_count: usize,
}

pub(super) struct PlannedParam {
    spec: ParamSpec,
    value: Option<ArgValue>,
}

impl Renderer {
    pub(super) fn new(dialect: Dialect) -> Self {
        Self {
            dialect,
            dialect_renderer: dialect::renderer(dialect),
            params: IndexMap::new(),
            bind_order: Vec::new(),
            var_names: HashMap::new(),
            named_vars: HashSet::new(),
            var_counter: 0,
            value_counter: 0,
            prebound_count: 0,
        }
    }

    pub(super) fn with_prebound(dialect: Dialect, prebound_count: usize) -> Self {
        Self {
            prebound_count,
            ..Self::new(dialect)
        }
    }

    pub(super) fn dialect(&self) -> Dialect {
        self.dialect
    }
}