is a very powerful feature of MyBatis. It enables programmers write the query using the dynamic
. MyBatis uses a powerful Dynamic
statement. Following are the OGNL based Dynamic
expressions provided by MyBatis when, otherwise trim where, set foreach The if Statement The most common thing to do in dynamic
is conditionally include a part of a where clause. For example −
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© 2018 Percona. 1 Peter Zaitsev Using MySQL for Distributed Database Architectures CEO, Percona PingCAP Infra Meetup, Shanghai, China, May 26, 2018 © 2018 Percona. 2 About Percona Solutions enterprises © 2018 Percona. 3 Presentation Cover Basics Why Going Distributed How to do it © 2018 Percona. 4 Distributed ? MySQL Deployment on More than one System © 2018 Percona. 5 Modern Active Users Possible 15M of Daily Active Users counting time of day skew © 2018 Percona. 8 Distributed Systems Tend To be More Complicated to Develop Against More Complicated to Operate Have
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C++20 ❤ SQL
John R Bandela, MDOverview
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SQL
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C++ Example
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Implementation techniques
u fixed_string
u meta_struct
u Parsing compile time strings into meta_structsOverview
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SQL
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C++ Example {price_from_user};Avoiding SQL Injection Attacks
SELECT orders.id, name, item, price, discount_code
FROM orders JOIN customers ON customers.id = customerid
WHERE price > ?;SQL Library Options
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Traditional Lots of information available
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Vulnerable to sql injection of developer not careful
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Use dynamic typingDomain Specific Language
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Use types to encode SQL
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Looks more like regular C++
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Typically requires
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Updates to a shared chat / drawing canvas – Game events © Joe Mertz – Mobile to Cloud: Building Distributed Applications • Workarounds have been devised • E.g. Polling – Client continuously polls the server stamp for the next time he wants to send a letter. © Joe Mertz – Mobile to Cloud: Building Distributed Applications • Provides for true two-way ongoing communication between a client and server. Note: – Some old browsers don't implement WebSockets © Joe Mertz – Mobile to Cloud: Building Distributed Applications // Create a new WebSocket var wSocket = new WebSocket("ws://www.example.com/socketserver")
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program for a supercomputer?
Introduce PGAS Model, RDMA
Building Remote Pointer Types
Building Distributed Data Structures
Extending to GPUsThis Talk
Background: how do we write a program for a supercomputer supercomputer?
Introduce PGAS Model, RDMA
Building Remote Pointer Types
Building Distributed Data Structures
Extending to GPUsThis Talk
Background: how do we write a program for a supercomputer?
Introduce Introduce PGAS Model, RDMA
Building Remote Pointer Types
Building Distributed Data Structures
Extending to GPUsThis Talk
Background: how do we write a program for a supercomputer?
Introduce PGAS Model
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Firebird Null Guide NULL behaviour and pitfalls in Firebird SQL Paul Vinkenoog Version 1.2, 30 June 2020 Table of Contents 1. What is NULL? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2. NULL support in Firebird SQL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . operations will render the entire expression NULL. This guide explores the behaviour of NULL in Firebird SQL , points out common pitfalls and shows you how to deal safely with expressions that contain NULL or
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TiDB: HBase分布式事务与SQL 实现 About me ● TiDB & Codis founder ● Golang expert ● Distributed database developer ● Currentlly, CEO and co-founder of PingCAP liuqi@pingcap.com https://github.com/pingcap/tidb say ? “Nothing is hotter than SQL -on-Hadoop, and now SQL -on- HBase is fast approaching equal hotness status” Form HBaseCon 2015 We want more ! SQL + Transaction(ACID) TiDB Features Features ● Consistent distributed transactions ○ TiDB makes your application code simple and robust. ● Compatible with MySQL protocol ○ Use TiDB as distributed MySQL. ○ Replace MySQL with TiDB to
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第三届中国Rust开发者⼤会 ⽤ egg 孵化你的 SQL 优化器 王润基 RisingWave 内核开发⼯程师 ? Parser Binder Optimizer Executor SQL AST Logical Plan Physical Plan Table Catalog Storage RisingLight 查询引擎的整体结构 SELECT name, url url FROM t1 JOIN t2 WHERE t1.id = t2.id AND name = ‘Bob’ SQL Logical Plan Physical Plan Projection name, url Filter t1.id = t2.id name = “Bob” Join Scan t1(id, name) Scan t2(id, url) Filter #1 = “Bob” Hash Join #0 = #2 Scan $1.1, $1.2 Scan $2.1, $2.2 Projection #1, #3 ⼀个 SQL 语句优化的例⼦ 基于规则的优化 (RBO) 基于代价的优化 (CBO) 谓词下推 Join Filter A B Join Filter A B Filter Join A Join
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