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
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173

use {
    super::{DataType, Expr},
    crate::ast::ToSql,
    serde::{Deserialize, Serialize},
};

#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum AlterTableOperation {
    /// `ADD [ COLUMN ] <column_def>`
    AddColumn { column_def: ColumnDef },
    /// `DROP [ COLUMN ] [ IF EXISTS ] <column_name> [ CASCADE ]`
    DropColumn {
        column_name: String,
        if_exists: bool,
    },
    /// `RENAME [ COLUMN ] <old_column_name> TO <new_column_name>`
    RenameColumn {
        old_column_name: String,
        new_column_name: String,
    },
    /// `RENAME TO <table_name>`
    RenameTable { table_name: String },
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub struct ColumnDef {
    pub name: String,
    pub data_type: DataType,
    pub options: Vec<ColumnOptionDef>,
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub struct ColumnOptionDef {
    pub name: Option<String>,
    pub option: ColumnOption,
}

#[derive(Debug, Clone, PartialEq, Eq, Hash, Serialize, Deserialize)]
pub enum ColumnOption {
    /// `NULL`
    Null,
    /// `NOT NULL`
    NotNull,
    /// `DEFAULT <restricted-expr>`
    Default(Expr),
    /// `{ PRIMARY KEY | UNIQUE }`
    Unique { is_primary: bool },
}

impl ToSql for AlterTableOperation {
    fn to_sql(&self) -> String {
        match self {
            AlterTableOperation::AddColumn { column_def } => {
                format!("ADD COLUMN {}", column_def.to_sql())
            }
            AlterTableOperation::DropColumn {
                column_name,
                if_exists,
            } => match if_exists {
                true => format!("DROP COLUMN IF EXISTS {column_name}"),
                false => format!("DROP COLUMN {column_name}"),
            },
            AlterTableOperation::RenameColumn {
                old_column_name,
                new_column_name,
            } => format!("RENAME COLUMN {old_column_name} TO {new_column_name}"),
            AlterTableOperation::RenameTable { table_name } => {
                format!("RENAME TO {table_name}")
            }
        }
    }
}

impl ToSql for ColumnDef {
    fn to_sql(&self) -> String {
        let ColumnDef {
            name,
            data_type,
            options,
        } = self;
        {
            let options = options
                .iter()
                .map(|ColumnOptionDef { option, .. }| option.to_sql())
                .collect::<Vec<_>>()
                .join(" ");

            format!("{name} {data_type} {options}")
                .trim_end()
                .to_owned()
        }
    }
}

impl ToSql for ColumnOption {
    fn to_sql(&self) -> String {
        match self {
            ColumnOption::Null => "NULL".to_owned(),
            ColumnOption::NotNull => "NOT NULL".to_owned(),
            ColumnOption::Default(expr) => format!("DEFAULT {}", expr.to_sql()),
            ColumnOption::Unique { is_primary } => match is_primary {
                true => "PRIMARY KEY".to_owned(),
                false => "UNIQUE".to_owned(),
            },
        }
    }
}

#[cfg(test)]
mod tests {
    use crate::ast::{AstLiteral, ColumnDef, ColumnOption, ColumnOptionDef, DataType, Expr, ToSql};

    #[test]
    fn to_sql_column_def() {
        assert_eq!(
            "name TEXT UNIQUE",
            ColumnDef {
                name: "name".to_owned(),
                data_type: DataType::Text,
                options: vec![ColumnOptionDef {
                    name: None,
                    option: ColumnOption::Unique { is_primary: false }
                }]
            }
            .to_sql()
        );

        assert_eq!(
            "accepted BOOLEAN NULL",
            ColumnDef {
                name: "accepted".to_owned(),
                data_type: DataType::Boolean,
                options: vec![ColumnOptionDef {
                    name: None,
                    option: ColumnOption::Null
                }]
            }
            .to_sql()
        );

        assert_eq!(
            "id INT NOT NULL PRIMARY KEY",
            ColumnDef {
                name: "id".to_owned(),
                data_type: DataType::Int,
                options: vec![
                    ColumnOptionDef {
                        name: None,
                        option: ColumnOption::NotNull
                    },
                    ColumnOptionDef {
                        name: None,
                        option: ColumnOption::Unique { is_primary: true }
                    }
                ]
            }
            .to_sql()
        );

        assert_eq!(
            "accepted BOOLEAN DEFAULT FALSE",
            ColumnDef {
                name: "accepted".to_owned(),
                data_type: DataType::Boolean,
                options: vec![ColumnOptionDef {
                    name: None,
                    option: ColumnOption::Default(Expr::Literal(AstLiteral::Boolean(false)))
                }]
            }
            .to_sql()
        );
    }
}