介绍

TCP协议是具有下列特性的传输层协议：

• 它是可靠的。这意味着TCP协议保证报文以正确的顺序传输，或者通知报文没有传输成功。TCP协议包含错误处理机制。
• 它假定建立逻辑连接。在一个程序通过TCP协议与另一个程序通信之前，它必须根据标准通过交换服务报文建立一个逻辑连接。
• 它假定点对点通信模型。也就是在单个连接上只有两个程序可以通信，不支持多播消息。
• 它是面向数据流的。这意味着一个程序发送给另一个程序的数据会被TCP协议解释为字节流。

UDP协议是一个与TCP协议不同的传输层协议，它具有下列特性：

5.0. Introduction

• A string can be binary or nonbinary. Binary strings are used for raw data such as images, music files, or encrypted values. Nonbinary strings are used for character data such as text and are associated with a character set and collation (sort order).
• A character set determines which characters are legal in a string. You can choose collations according to whether you need comparisons to be case sensitive or case insensitive, or to use the rules of a particular language.
• Data types for binary strings are BINARY, VARBINARY, and BLOB. Data types for nonbinary strings are CHAR, VARCHAR, and TEXT, each of which permits CHARACTER SET and COLLATE attributes.
• You can convert a binary string to a nonbinary string and vice versa, or convert a nonbinary string from one character set or collation to another.
• You can use a string in its entirety or extract substrings from it. Strings can be combined with other strings.
• You can apply pattern-matching operations to strings.
• Full-text searching is available for efficient queries on large collections of text.

5.1. String Properties

One string property is whether it is binary or nonbinary:

4.0. Introduction

This chapter covers topics that relate to creating and populating tables: • Cloning a table • Copying from one table to another • Using temporary tables • Generating unique table names • Determining what storage engine a table uses or converting it from one storage engine to another

4.1. Cloning a Table

Problem

You want to create a table that has exactly the same structure as an existing table.

3.0. 介绍

本章专注使用SELECT语句从你的数据库获取信息。

3.1. 指定SELECT哪行哪列

问题

你想要从一张表中展示特定行和列。

解决方法

为了指示展示哪一列，在输出列表中指定它。为了指示展示哪一行，使用WHERE语句指定满足条件的行。

2.0. 介绍

MySQL Client API Architecture

Each MySQL programming interface covered in this book uses a two-level architecture:

• The upper level provides database-independent methods that implement database access in a portable way that’s the same whether you use MySQL, PostgreSQL, Ora‐ cle, or whatever.
• The lower level consists of a set of drivers, each of which implements the details for a single database system.

2.1. Connecting, Selecting a Database, and Disconnecting

Problem