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172#sql-query

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64 个 crate 中使用 (通过 sea-query)

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SeaQuery logo

🔱 MySQL、Postgres 和 SQLite 的动态查询构建器

crate docs build status

SeaQuery

SeaQuery 是一个查询构建器,帮助您在 Rust 中构建动态 SQL 查询。您可以使用直观的 API 构建表达式、查询和模式,作为抽象语法树。我们支持 MySQL、Postgres 和 SQLite,通过一个通用的接口提供支持,并在适当的地方对它们的行为进行对齐。

我们为 SQLxpostgresrusqlite 提供了集成。请参阅 示例 了解使用方法。

SeaQuery 是 SeaORM 的基础,SeaORM 是一个 Rust 的异步动态 ORM。

GitHub stars 如果您喜欢我们所做的工作,请考虑点赞、评论、分享和贡献!

Discord 加入我们的 Discord 服务器,与其他 SeaQL 社区成员交流!

安装

# Cargo.toml
[dependencies]
sea-query = "0"

SeaQuery 非常轻量级,所有依赖项都是可选的(除了 inherent)。

功能标志

宏:derive attr

异步支持:thread-safe(使用 Arc 代替 Rc

SQL 引擎:backend-mysqlbackend-postgresbackend-sqlite

类型支持:with-chronowith-timewith-jsonwith-rust_decimalwith-bigdecimalwith-uuidwith-ipnetworkwith-mac_addresspostgres-arraypostgres-interval

使用方法

目录

  1. 基础

    1. Iden
    2. 表达式
    3. 条件
    4. 语句构建器
  2. 查询语句

    1. 查询选择
    2. 查询插入
    3. 查询更新
    4. 查询删除
  3. 高级

    1. 聚合函数
    2. 类型转换
    3. 自定义函数
  4. 模式语句

    1. 创建表
    2. 修改表
    3. 删除表
    4. 重命名表
    5. 截断表
    6. 创建外键
    7. 删除外键
    8. 创建索引
    9. 删除索引

动机

你为什么想使用动态查询构建器?

  1. 参数绑定

使用原始SQL时,参数绑定是一个头疼的问题。使用SeaQuery,你可以

assert_eq!(
    Query::select()
        .column(Glyph::Image)
        .from(Glyph::Table)
        .and_where(Expr::col(Glyph::Image).like("A"))
        .and_where(Expr::col(Glyph::Id).is_in([1, 2, 3]))
        .build(PostgresQueryBuilder),
    (
        r#"SELECT "image" FROM "glyph" WHERE "image" LIKE $1 AND "id" IN ($2, $3, $4)"#
            .to_owned(),
        Values(vec![
            Value::String(Some(Box::new("A".to_owned()))),
            Value::Int(Some(1)),
            Value::Int(Some(2)),
            Value::Int(Some(3))
        ])
    )
);
  1. 动态查询

根据用户输入在运行时构建查询

Query::select()
    .column(Char::Character)
    .from(Char::Table)
    .conditions(
        // some runtime condition
        true,
        // if condition is true then add the following condition
        |q| {
            q.and_where(Expr::col(Char::Id).eq(1));
        },
        // otherwise leave it as is
        |q| {},
    );

Iden

Iden 是任何查询语句中使用的标识符的 trait。

通常由 Enum 实现,其中每个 Enum 代表数据库中找到的表,其变体包括表名和列名。

[Iden::unquoted()] 必须实现,以提供 Enum 变体与其对应的字符串值之间的映射。

use sea_query::*;

// For example Character table with column id, character, font_size...
pub enum Character {
    Table,
    Id,
    FontId,
    FontSize,
}

// Mapping between Enum variant and its corresponding string value
impl Iden for Character {
    fn unquoted(&self, s: &mut dyn std::fmt::Write) {
        write!(
            s,
            "{}",
            match self {
                Self::Table => "character",
                Self::Id => "id",
                Self::FontId => "font_id",
                Self::FontSize => "font_size",
            }
        )
        .unwrap();
    }
}

如果你愿意运行另一个过程宏,可以在 crate 上激活 deriveattr 功能以节省一些样板代码。有关更多信息,请参阅derive 示例属性示例

#[cfg(feature = "derive")]
use sea_query::Iden;

// This will implement Iden exactly as shown above
#[derive(Iden)]
enum Character {
    Table,
}
assert_eq!(Character::Table.to_string(), "character");

// You can also derive a unit struct
#[derive(Iden)]
struct Glyph;
assert_eq!(Glyph.to_string(), "glyph");
#[cfg(feature = "attr")]
use sea_query::{enum_def, Iden};

#[enum_def]
struct Character {
    pub foo: u64,
}

// It generates the following along with Iden impl
enum CharacterIden {
    Table,
    Foo,
}

assert_eq!(CharacterIden::Table.to_string(), "character");
assert_eq!(CharacterIden::Foo.to_string(), "foo");

表达式

使用 Expr 在查询中构建选择、连接、where 和 having 表达式。

assert_eq!(
    Query::select()
        .column(Char::Character)
        .from(Char::Table)
        .and_where(
            Expr::expr(Expr::col(Char::SizeW).add(1))
                .mul(2)
                .eq(Expr::expr(Expr::col(Char::SizeH).div(2)).sub(1))
        )
        .and_where(
            Expr::col(Char::SizeW).in_subquery(
                Query::select()
                    .expr(Expr::cust_with_values("ln($1 ^ $2)", [2.4, 1.2]))
                    .take()
            )
        )
        .and_where(
            Expr::col(Char::Character)
                .like("D")
                .and(Expr::col(Char::Character).like("E"))
        )
        .to_string(PostgresQueryBuilder),
    [
        r#"SELECT "character" FROM "character""#,
        r#"WHERE ("size_w" + 1) * 2 = ("size_h" / 2) - 1"#,
        r#"AND "size_w" IN (SELECT ln(2.4 ^ 1.2))"#,
        r#"AND (("character" LIKE 'D') AND ("character" LIKE 'E'))"#,
    ]
    .join(" ")
);

条件

如果你有复杂的条件要表达,可以使用 Condition 构建器,适用于 ConditionalStatement::cond_whereSelectStatement::cond_having

assert_eq!(
    Query::select()
        .column(Glyph::Id)
        .from(Glyph::Table)
        .cond_where(
            Cond::any()
                .add(
                    Cond::all()
                        .add(Expr::col(Glyph::Aspect).is_null())
                        .add(Expr::col(Glyph::Image).is_null())
                )
                .add(
                    Cond::all()
                        .add(Expr::col(Glyph::Aspect).is_in([3, 4]))
                        .add(Expr::col(Glyph::Image).like("A%"))
                )
        )
        .to_string(PostgresQueryBuilder),
    [
        r#"SELECT "id" FROM "glyph""#,
        r#"WHERE"#,
        r#"("aspect" IS NULL AND "image" IS NULL)"#,
        r#"OR"#,
        r#"("aspect" IN (3, 4) AND "image" LIKE 'A%')"#,
    ]
    .join(" ")
);

还有方便使用的 any!all!

Query::select().cond_where(any![
    Expr::col(Glyph::Aspect).is_in([3, 4]),
    all![
        Expr::col(Glyph::Aspect).is_null(),
        Expr::col(Glyph::Image).like("A%")
    ]
]);

语句构建器

语句分为 2 类:查询和模式,并分别通过 QueryStatementBuilderSchemaStatementBuilder 序列化为 SQL。

模式语句具有以下接口

fn build<T: SchemaBuilder>(&self, schema_builder: T) -> String;

查询语句具有以下接口

fn build<T: QueryBuilder>(&self, query_builder: T) -> (String, Values);

fn to_string<T: QueryBuilder>(&self, query_builder: T) -> String;

build 以字符串形式构建 SQL 语句,并通过二进制协议将参数传递给数据库驱动程序。这是首选方式,因为它具有更少的开销且更安全。

to_string 以字符串形式构建 SQL 语句,并注入参数。这对于测试和调试很有用。

查询选择

let query = Query::select()
    .column(Char::Character)
    .column((Font::Table, Font::Name))
    .from(Char::Table)
    .left_join(Font::Table, Expr::col((Char::Table, Char::FontId)).equals((Font::Table, Font::Id)))
    .and_where(Expr::col(Char::SizeW).is_in([3, 4]))
    .and_where(Expr::col(Char::Character).like("A%"))
    .to_owned();

assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"SELECT `character`, `font`.`name` FROM `character` LEFT JOIN `font` ON `character`.`font_id` = `font`.`id` WHERE `size_w` IN (3, 4) AND `character` LIKE 'A%'"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"SELECT "character", "font"."name" FROM "character" LEFT JOIN "font" ON "character"."font_id" = "font"."id" WHERE "size_w" IN (3, 4) AND "character" LIKE 'A%'"#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"SELECT "character", "font"."name" FROM "character" LEFT JOIN "font" ON "character"."font_id" = "font"."id" WHERE "size_w" IN (3, 4) AND "character" LIKE 'A%'"#
);

查询插入

let query = Query::insert()
    .into_table(Glyph::Table)
    .columns([Glyph::Aspect, Glyph::Image])
    .values_panic([5.15.into(), "12A".into()])
    .values_panic([4.21.into(), "123".into()])
    .to_owned();

assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"INSERT INTO `glyph` (`aspect`, `image`) VALUES (5.15, '12A'), (4.21, '123')"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"INSERT INTO "glyph" ("aspect", "image") VALUES (5.15, '12A'), (4.21, '123')"#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"INSERT INTO "glyph" ("aspect", "image") VALUES (5.15, '12A'), (4.21, '123')"#
);

查询更新

let query = Query::update()
    .table(Glyph::Table)
    .values([(Glyph::Aspect, 1.23.into()), (Glyph::Image, "123".into())])
    .and_where(Expr::col(Glyph::Id).eq(1))
    .to_owned();

assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"UPDATE `glyph` SET `aspect` = 1.23, `image` = '123' WHERE `id` = 1"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"UPDATE "glyph" SET "aspect" = 1.23, "image" = '123' WHERE "id" = 1"#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"UPDATE "glyph" SET "aspect" = 1.23, "image" = '123' WHERE "id" = 1"#
);

查询删除

let query = Query::delete()
    .from_table(Glyph::Table)
    .cond_where(
        Cond::any()
            .add(Expr::col(Glyph::Id).lt(1))
            .add(Expr::col(Glyph::Id).gt(10)),
    )
    .to_owned();

assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"DELETE FROM `glyph` WHERE `id` < 1 OR `id` > 10"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"DELETE FROM "glyph" WHERE "id" < 1 OR "id" > 10"#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"DELETE FROM "glyph" WHERE "id" < 1 OR "id" > 10"#
);

聚合函数

maxminsumavgcount

let query = Query::select()
    .expr(Func::sum(Expr::col((Char::Table, Char::SizeH))))
    .from(Char::Table)
    .to_owned();
assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"SELECT SUM(`character`.`size_h`) FROM `character`"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"SELECT SUM("character"."size_h") FROM "character""#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"SELECT SUM("character"."size_h") FROM "character""#
);

类型转换

let query = Query::select()
    .expr(Func::cast_as("hello", Alias::new("MyType")))
    .to_owned();

assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"SELECT CAST('hello' AS MyType)"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"SELECT CAST('hello' AS MyType)"#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"SELECT CAST('hello' AS MyType)"#
);

自定义函数

struct MyFunction;

impl Iden for MyFunction {
    fn unquoted(&self, s: &mut dyn Write) {
        write!(s, "MY_FUNCTION").unwrap();
    }
}

let query = Query::select()
    .expr(Func::cust(MyFunction).arg(Expr::val("hello")))
    .to_owned();

assert_eq!(
    query.to_string(MysqlQueryBuilder),
    r#"SELECT MY_FUNCTION('hello')"#
);
assert_eq!(
    query.to_string(PostgresQueryBuilder),
    r#"SELECT MY_FUNCTION('hello')"#
);
assert_eq!(
    query.to_string(SqliteQueryBuilder),
    r#"SELECT MY_FUNCTION('hello')"#
);

创建表

let table = Table::create()
    .table(Char::Table)
    .if_not_exists()
    .col(ColumnDef::new(Char::Id).integer().not_null().auto_increment().primary_key())
    .col(ColumnDef::new(Char::FontSize).integer().not_null())
    .col(ColumnDef::new(Char::Character).string().not_null())
    .col(ColumnDef::new(Char::SizeW).integer().not_null())
    .col(ColumnDef::new(Char::SizeH).integer().not_null())
    .col(ColumnDef::new(Char::FontId).integer().default(Value::Int(None)))
    .foreign_key(
        ForeignKey::create()
            .name("FK_2e303c3a712662f1fc2a4d0aad6")
            .from(Char::Table, Char::FontId)
            .to(Font::Table, Font::Id)
            .on_delete(ForeignKeyAction::Cascade)
            .on_update(ForeignKeyAction::Cascade)
    )
    .to_owned();

assert_eq!(
    table.to_string(MysqlQueryBuilder),
    [
        r#"CREATE TABLE IF NOT EXISTS `character` ("#,
            r#"`id` int NOT NULL AUTO_INCREMENT PRIMARY KEY,"#,
            r#"`font_size` int NOT NULL,"#,
            r#"`character` varchar(255) NOT NULL,"#,
            r#"`size_w` int NOT NULL,"#,
            r#"`size_h` int NOT NULL,"#,
            r#"`font_id` int DEFAULT NULL,"#,
            r#"CONSTRAINT `FK_2e303c3a712662f1fc2a4d0aad6`"#,
                r#"FOREIGN KEY (`font_id`) REFERENCES `font` (`id`)"#,
                r#"ON DELETE CASCADE ON UPDATE CASCADE"#,
        r#")"#,
    ].join(" ")
);
assert_eq!(
    table.to_string(PostgresQueryBuilder),
    [
        r#"CREATE TABLE IF NOT EXISTS "character" ("#,
            r#""id" serial NOT NULL PRIMARY KEY,"#,
            r#""font_size" integer NOT NULL,"#,
            r#""character" varchar NOT NULL,"#,
            r#""size_w" integer NOT NULL,"#,
            r#""size_h" integer NOT NULL,"#,
            r#""font_id" integer DEFAULT NULL,"#,
            r#"CONSTRAINT "FK_2e303c3a712662f1fc2a4d0aad6""#,
                r#"FOREIGN KEY ("font_id") REFERENCES "font" ("id")"#,
                r#"ON DELETE CASCADE ON UPDATE CASCADE"#,
        r#")"#,
    ].join(" ")
);
assert_eq!(
    table.to_string(SqliteQueryBuilder),
    [
       r#"CREATE TABLE IF NOT EXISTS "character" ("#,
           r#""id" integer NOT NULL PRIMARY KEY AUTOINCREMENT,"#,
           r#""font_size" integer NOT NULL,"#,
           r#""character" text NOT NULL,"#,
           r#""size_w" integer NOT NULL,"#,
           r#""size_h" integer NOT NULL,"#,
           r#""font_id" integer DEFAULT NULL,"#,
           r#"FOREIGN KEY ("font_id") REFERENCES "font" ("id") ON DELETE CASCADE ON UPDATE CASCADE"#,
       r#")"#,
    ].join(" ")
);

修改表

let table = Table::alter()
    .table(Font::Table)
    .add_column(
        ColumnDef::new(Alias::new("new_col"))
            .integer()
            .not_null()
            .default(100),
    )
    .to_owned();

assert_eq!(
    table.to_string(MysqlQueryBuilder),
    r#"ALTER TABLE `font` ADD COLUMN `new_col` int NOT NULL DEFAULT 100"#
);
assert_eq!(
    table.to_string(PostgresQueryBuilder),
    r#"ALTER TABLE "font" ADD COLUMN "new_col" integer NOT NULL DEFAULT 100"#
);
assert_eq!(
    table.to_string(SqliteQueryBuilder),
    r#"ALTER TABLE "font" ADD COLUMN "new_col" integer NOT NULL DEFAULT 100"#,
);

删除表

let table = Table::drop()
    .table(Glyph::Table)
    .table(Char::Table)
    .to_owned();

assert_eq!(
    table.to_string(MysqlQueryBuilder),
    r#"DROP TABLE `glyph`, `character`"#
);
assert_eq!(
    table.to_string(PostgresQueryBuilder),
    r#"DROP TABLE "glyph", "character""#
);
assert_eq!(
    table.to_string(SqliteQueryBuilder),
    r#"DROP TABLE "glyph", "character""#
);

重命名表

let table = Table::rename()
    .table(Font::Table, Alias::new("font_new"))
    .to_owned();

assert_eq!(
    table.to_string(MysqlQueryBuilder),
    r#"RENAME TABLE `font` TO `font_new`"#
);
assert_eq!(
    table.to_string(PostgresQueryBuilder),
    r#"ALTER TABLE "font" RENAME TO "font_new""#
);
assert_eq!(
    table.to_string(SqliteQueryBuilder),
    r#"ALTER TABLE "font" RENAME TO "font_new""#
);

截断表

let table = Table::truncate().table(Font::Table).to_owned();

assert_eq!(
    table.to_string(MysqlQueryBuilder),
    r#"TRUNCATE TABLE `font`"#
);
assert_eq!(
    table.to_string(PostgresQueryBuilder),
    r#"TRUNCATE TABLE "font""#
);
// Sqlite does not support the TRUNCATE statement

创建外键

let foreign_key = ForeignKey::create()
    .name("FK_character_font")
    .from(Char::Table, Char::FontId)
    .to(Font::Table, Font::Id)
    .on_delete(ForeignKeyAction::Cascade)
    .on_update(ForeignKeyAction::Cascade)
    .to_owned();

assert_eq!(
    foreign_key.to_string(MysqlQueryBuilder),
    [
        r#"ALTER TABLE `character`"#,
        r#"ADD CONSTRAINT `FK_character_font`"#,
        r#"FOREIGN KEY (`font_id`) REFERENCES `font` (`id`)"#,
        r#"ON DELETE CASCADE ON UPDATE CASCADE"#,
    ]
    .join(" ")
);
assert_eq!(
    foreign_key.to_string(PostgresQueryBuilder),
    [
        r#"ALTER TABLE "character" ADD CONSTRAINT "FK_character_font""#,
        r#"FOREIGN KEY ("font_id") REFERENCES "font" ("id")"#,
        r#"ON DELETE CASCADE ON UPDATE CASCADE"#,
    ]
    .join(" ")
);
// Sqlite does not support modification of foreign key constraints to existing tables

删除外键

let foreign_key = ForeignKey::drop()
    .name("FK_character_font")
    .table(Char::Table)
    .to_owned();

assert_eq!(
    foreign_key.to_string(MysqlQueryBuilder),
    r#"ALTER TABLE `character` DROP FOREIGN KEY `FK_character_font`"#
);
assert_eq!(
    foreign_key.to_string(PostgresQueryBuilder),
    r#"ALTER TABLE "character" DROP CONSTRAINT "FK_character_font""#
);
// Sqlite does not support modification of foreign key constraints to existing tables

创建索引

let index = Index::create()
    .name("idx-glyph-aspect")
    .table(Glyph::Table)
    .col(Glyph::Aspect)
    .to_owned();

assert_eq!(
    index.to_string(MysqlQueryBuilder),
    r#"CREATE INDEX `idx-glyph-aspect` ON `glyph` (`aspect`)"#
);
assert_eq!(
    index.to_string(PostgresQueryBuilder),
    r#"CREATE INDEX "idx-glyph-aspect" ON "glyph" ("aspect")"#
);
assert_eq!(
    index.to_string(SqliteQueryBuilder),
    r#"CREATE INDEX "idx-glyph-aspect" ON "glyph" ("aspect")"#
);

删除索引

let index = Index::drop()
    .name("idx-glyph-aspect")
    .table(Glyph::Table)
    .to_owned();

assert_eq!(
    index.to_string(MysqlQueryBuilder),
    r#"DROP INDEX `idx-glyph-aspect` ON `glyph`"#
);
assert_eq!(
    index.to_string(PostgresQueryBuilder),
    r#"DROP INDEX "idx-glyph-aspect""#
);
assert_eq!(
    index.to_string(SqliteQueryBuilder),
    r#"DROP INDEX "idx-glyph-aspect""#
);

许可证

根据以下任一项许可

由你选择。

贡献

除非您明确说明,否则您根据Apache-2.0许可证定义提交给作品的所有贡献,均应以上述方式双重许可,不附加任何额外条款或条件。

SeaQuery是一个社区驱动的项目。我们欢迎您参与、贡献,共同为Rust的未来建设。

向我们的贡献者致以崇高的敬意

Contributors

依赖项

~0.3–0.8MB
~19K SLoC