C++ 安全 SQL 模版库 sqlpp11
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sqlpp11 是 C++ 的类型安全 SQL 模版库。
sqlpp11 是一个嵌入式领域特定语言(EDSL)的代表模版库:
为表和列定义类型
在编译的时候检查结构类型安全查询(语法错误,类型错误,命名错误,甚至是一些语义错误)
通过迭代 query-specific 结构得到解析结果
示例
CREATE TABLE foo ( id bigint, name varchar(50), hasFun bool);假设有个数据库连接对象:
TabFoo foo;Db db(/* some arguments*/);// selecting zero or more results, iterating over the resultsfor (const auto& row : db(select(foo.name, foo.hasFun).from(foo).where(foo.id > 17 and foo.name.like("%bar%")))){ if (row.name.is_null()) std::cerr << "name is null, will convert to empty string" << std::endl; std::string name = row.name; // string-like fields are implicitly convertible to string bool hasFun = row.hasFun; // bool fields are implicitly convertible to bool}// selecting ALL columns of a tablefor (const auto& row : db(select(all_of(foo)).from(foo).where(foo.hasFun or foo.name == "joker"))){ int64_t id = row.id; // numeric fields are implicitly convertible to numeric c++ types}// selecting zero or one row, showing off with an alias:SQLPP_ALIAS_PROVIDER(cheese);if (const auto& row = db(select(foo.name.as(cheese)).from(foo).where(foo.id == 17))){ std::cerr << "found: " << row.cheese << std::endl;}// selecting a single row with a single result:return db(select(count(foo.id)).from(foo).where(true)).front().count;Of course there are joins and subqueries, more functions, order_by, group_by etc.These will be documented soon.// A sample insertdb(insert_into(foo).set(foo.id = 17, foo.name = "bar", foo.hasFun = true));// A sample updatedb(update(foo).set(foo.hasFun = not foo.hasFun).where(foo.name != "nobody"));// A sample deletedb(remove_from(foo).where(not foo.hasFun));