Trait DatabaseInfo 

pub trait DatabaseInfo: Database {
    // Required methods
    fn placeholder(index: usize) -> String;
    fn escape_identifier(name: &str) -> String;
    fn get_driver() -> DbDriver;
}

数据库信息 trait

为不同的数据库类型提供统一的接口，用于获取数据库特定的信息， 如占位符格式、标识符转义方式等。

实现要求

每个数据库类型（sqlx::MySql, sqlx::Postgres, sqlx::Sqlite） 都需要实现此 trait，以提供数据库特定的行为。

Required Methods

fn placeholder(index: usize) -> String

获取占位符字符串

参数

• index - 占位符的索引（从 0 开始）

返回值

• MySQL/SQLite: "?"
• PostgreSQL: "$1", "$2", … (index + 1)

示例

assert_eq!(<sqlx::MySql as DatabaseInfo>::placeholder(0), "?");
assert_eq!(<sqlx::Postgres as DatabaseInfo>::placeholder(0), "$1");
assert_eq!(<sqlx::Postgres as DatabaseInfo>::placeholder(1), "$2");

fn escape_identifier(name: &str) -> String

转义 SQL 标识符（表名、列名等）

参数

• name - 需要转义的标识符名称

返回值

• MySQL: `name`
• PostgreSQL/SQLite: "name"

示例

assert_eq!(<sqlx::MySql as DatabaseInfo>::escape_identifier("user"), "`user`");
assert_eq!(<sqlx::Postgres as DatabaseInfo>::escape_identifier("user"), "\"user\"");

fn get_driver() -> DbDriver

获取数据库驱动类型

返回值

对应的 DbDriver 枚举值

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementations on Foreign Types

impl DatabaseInfo for MySql

Available on crate feature mysql only.

fn placeholder(_index: usize) -> String

fn escape_identifier(name: &str) -> String

fn get_driver() -> DbDriver

impl DatabaseInfo for Postgres

Available on crate feature postgres only.

fn placeholder(index: usize) -> String

fn escape_identifier(name: &str) -> String

fn get_driver() -> DbDriver

impl DatabaseInfo for Sqlite

Available on crate feature sqlite only.

fn placeholder(_index: usize) -> String

fn escape_identifier(name: &str) -> String

fn get_driver() -> DbDriver

Implementors