. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 578 13.3.2 Sharding Why does float number appear in the return result of inline expression?578 13.3.3 Sharding If sharding database is partial index. When the data amount exceeds the threshold, deeper index will increase the disk IO access number, and thereby, weaken the performance of query. In the same time, high concurrency requests also data in native distributed NoSQL. But its incom‐ patibility with SQL and imperfection in ecosystem block it from defeating the relational database in the competition, so the relational database still holds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 549 13.4.2 Sharding Why does float number appear in the return result of inline expression?550 13.4.3 Sharding If sharding database is partial index. When the data amount exceeds the threshold, deeper index will increase the disk IO access number, and thereby, weaken the performance of query. In the same time, high concurrency requests also data in native distributed NoSQL. But its incom‐ patibility with SQL and imperfection in ecosystem block it from defeating the relational database in the competition, so the relational database still holds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 457 8.3.2 Sharding Why does float number appear in the return result of inline expression?457 8.3.3 Sharding If sharding database is partial index. When the data amount exceeds the threshold, deeper index will increase the disk IO access number, and thereby, weaken the performance of query. In the same time, high concurrency requests also data in native distributed NoSQL. But its incom‐ patibility with SQL and imperfection in ecosystem block it from defeating the relational database in the competition, so the relational database still holds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 496 8.3.2 Sharding Why does float number appear in the return result of inline expression?496 8.3.3 Sharding If sharding database is partial index. When the data amount exceeds the threshold, deeper index will increase the disk IO access number, and thereby, weaken the performance of query. In the same time, high concurrency requests also data in native distributed NoSQL. But its incom‐ patibility with SQL and imperfection in ecosystem block it from defeating the relational database in the competition, so the relational database still holds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 360 7.8.9 [Sharding] Why does float number appear in the return result of inline expression?360 7.8.10 [Sharding] If sharding database is partial index. When the data amount exceeds the threshold, deeper index will increase the disk IO access number, and thereby, weaken the performance of query. In the same time, high concurrency requests also data in native distributed NoSQL. But its incom‐ patibility with SQL and imperfection in ecosystem block it from defeating the relational database in the competition, so the relational database still holds

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 348 7.8.9 [Sharding] Why does float number appear in the return result of inline expression?348 7.8.10 [Sharding] If sharding database is partial index. When the data amount exceeds the threshold, deeper index will increase the disk IO access number, and thereby, weaken the performance of query. In the same time, high concurrency requests also data in native distributed NoSQL. But its incom‐ patibility with SQL and imperfection in ecosystem block it from defeating the relational database in the competition, so the relational database still holds

Auto-generated catch block e.printStackTrace(); } } if(preparedStatement!=null){ try { preparedStatement.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); if(connection!=null){ try { connection.close(); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } } 上边使用 jdbc 的原始方法（未经封装）实现了查询数据库表记录的操作。 1.1.2 jdbc 编程步骤： 1、 加载数据库驱动 property="id" column="id"/> 3