Merge pull request astaxie#841 from vCaesar/u13-pr

Fix some md error and Add en syntax highlighting

Author: astaxie

README.md

@@ -22,7 +22,7 @@ QQ群：148647580
 
 BBS：[http://golanghome.com/](http://gocn.io/)
 
-##Contributors
+## Contributors
 
 - See [contributors page](https://github.com/astaxie/build-web-application-with-golang/graphs/contributors) for full list of contributors.
 

en/05.1.md

@@ -7,7 +7,7 @@ Go doesn't provide any official database drivers, unlike other languages like PH
 This function is in the `database/sql` package for registering database drivers when you use third-party database drivers. All of these should call the `Register(name string, driver driver.Driver)` function in `init()` in order to register themselves.
 
 Let's take a look at the corresponding mymysql and sqlite3 driver code:
-
+```Go
 	//https://github.com/mattn/go-sqlite3 driver
 	func init() {
 	    sql.Register("sqlite3", &SQLiteDriver{})
@@ -20,68 +20,68 @@ Let's take a look at the corresponding mymysql and sqlite3 driver code:
 	    Register("SET NAMES utf8")
 	    sql.Register("mymysql", &d)
 	}
-
+```
 We see that all third-party database drivers implement this function to register themselves, and Go uses a map to save user drivers inside of `database/sql`.
-
+```Go
 	var drivers = make(map[string]driver.Driver)
 
 	drivers[name] = driver
-
+```
 Therefore, this registration function can register as many drivers as you may require, each with different names.
 
 We always see the following code when we use third-party drivers:
-
+```Go
     import (
         "database/sql"
         _ "github.com/mattn/go-sqlite3"
     )
-
+```
 Here, the underscore (also known as a 'blank') `_` can be quite confusing for many beginners, but this is a great feature in Go. We already know that this underscore identifier is used for discarding values from function returns, and also that you must use all packages that you've imported in your code in Go. So when the blank is used with import, it means that you need to execute the init() function of that package without directly using it, which is a perfect fit for the use-case of registering database drivers.
 
 ## driver.Driver
 
 `Driver` is an interface containing an `Open(name string)` method that returns a `Conn` interface.
-
+```Go
 	type Driver interface {
 	    Open(name string) (Conn, error)
 	}
-
+```
 This is a one-time Conn, which means it can only be used once per goroutine. The following code will cause errors to occur:
-
+```Go
 	...
 	go goroutineA (Conn)  // query
 	go goroutineB (Conn)  // insert
 	...
-
+```
 Because Go has no idea which goroutine does which operation, the query operation may get the result of the insert operation, and vice-versa.
 
 All third-party drivers should have this function to parse the name of Conn and return the correct results.
 
 ## driver.Conn
 
 This is a database connection interface with some methods, and as i've said above, the same Conn can only be used once per goroutine.
-
+```Go
 	type Conn interface {
 	    Prepare(query string) (Stmt, error)
 	    Close() error
 	    Begin() (Tx, error)
 	}
-
+```
 - `Prepare` returns the prepare status of corresponding SQL commands for querying and deleting, etc.
 - `Close` closes the current connection and cleans resources. Most third-party drivers implement some kind of connection pool, so you don't need to cache connections which can cause unexpected errors.
 - `Begin` returns a Tx that represents a transaction handle. You can use it for querying, updating, rolling back transactions, etc.
 
 ## driver.Stmt
 
 This is a ready status that corresponds with Conn, so it can only be used once per goroutine (as is the case with Conn).
-
+```Go
 	type Stmt interface {
 	    Close() error
 	    NumInput() int
 	    Exec(args []Value) (Result, error)
 	    Query(args []Value) (Rows, error)
 	}
-
+```
 - `Close` closes the current connection but still returns row data if it is executing a query operation.
 - `NumInput` returns the number of obligate arguments. Database drivers should check their caller's arguments when the result is greater than 0, and it returns -1 when database drivers don't know any obligate argument.
 - `Exec` executes the `update/insert` SQL commands prepared in `Prepare`, returns `Result`.
@@ -90,81 +90,81 @@ This is a ready status that corresponds with Conn, so it can only be used once p
 ## driver.Tx
 
 Generally, transaction handles only have submit or rollback methods, and database drivers only need to implement these two methods.
-
+```Go
 	type Tx interface {
 	    Commit() error
 	    Rollback() error
 	}
-
+```
 ## driver.Execer
 
 This is an optional interface.
-
+```Go
 	type Execer interface {
 	    Exec(query string, args []Value) (Result, error)
 	}
-
+```
 If the driver doesn't implement this interface, when you call DB.Exec, it will automatically call Prepare, then return Stmt. After that it executes the Exec method of Stmt, then closes Stmt.
 
 ## driver.Result
 
 This is the interface for results of `update/insert` operations.
-
+```Go
 	type Result interface {
 	    LastInsertId() (int64, error)
 	    RowsAffected() (int64, error)
 	}
-
+```
 - `LastInsertId` returns auto-increment Id number after a database insert operation.
 - `RowsAffected` returns rows that were affected by query operations.
 
 ## driver.Rows
 
 This is the interface for the result of a query operation.
-
+```Go
 	type Rows interface {
 	    Columns() []string
 	    Close() error
 	    Next(dest []Value) error
 	}
-
+```
 - `Columns` returns field information of database tables. The slice has a one-to-one correspondence with SQL query fields only, and does not return all fields of that database table.
 - `Close` closes Rows iterator.
 - `Next` returns next data and assigns to dest, converting all strings into byte arrays, and gets io.EOF error if no more data is available.
 
 ## driver.RowsAffected
 
 This is an alias of int64, but it implements the Result interface.
-
+```Go
 	type RowsAffected int64
 
 	func (RowsAffected) LastInsertId() (int64, error)
 
 	func (v RowsAffected) RowsAffected() (int64, error)
-
+```
 ## driver.Value
 
 This is an empty interface that can contain any kind of data.
-
+```Go
 	type Value interface{}
-
+```
 The Value must be something that drivers can operate on or nil, so it should be one of the following types:
-
+```Go
 	int64
 	float64
 	bool
 	[]byte
 	string   [*] Except Rows.Next which cannot return string
 	time.Time
-
+```
 ## driver.ValueConverter
 
 This defines an interface for converting normal values to driver.Value.
-
+```Go
 	type ValueConverter interface {
 	    ConvertValue(v interface{}) (Value, error)
 	}
-
+```
 This interface is commonly used in database drivers and has many useful features:
 
 - Converts driver.Value to a corresponding database field type, for example converts int64 to uint16.
@@ -174,27 +174,27 @@ This interface is commonly used in database drivers and has many useful features
 ## driver.Valuer
 
 This defines an interface for returning driver.Value.
-
+```Go
 	type Valuer interface {
 	    Value() (Value, error)
 	}
-
+```
 Many types implement this interface for conversion between driver.Value and itself.
 
 At this point, you should know a bit about developing database drivers in Go. Once you can implement interfaces for operations like add, delete, update, etc., there are only a few problems left related to communicating with specific databases.
 
 ## database/sql
 
 database/sql defines even more high-level methods on top of database/sql/driver for more convenient database operations, and it suggests that you implement a connection pool.
-
+```Go
 	type DB struct {
 	    driver   driver.Driver
 	    dsn      string
 	    mu       sync.Mutex // protects freeConn and closed
 	    freeConn []driver.Conn
 	    closed   bool
 	}
-
+```
 As you can see, the `Open` function returns a DB that has a freeConn, and this is a simple connection pool. Its implementation is very simple and ugly. It uses `defer db.putConn(ci, err)` in the Db.prepare function to put a connection into the connection pool. Everytime you call the Conn function, it checks the length of freeConn. If it's greater than 0, that means there is a reusable connection and it directly returns to you. Otherwise it creates a new connection and returns.
 
 ## Links

en/05.2.md

@@ -18,17 +18,17 @@ I'll use the first driver in the following examples (I use this one in my person
 ## Samples
 
 In the following sections, I'll use the same database table structure for different databases, then create SQL as follows:
-
+```sql
 	CREATE TABLE `userinfo` (
 	    `uid` INT(10) NOT NULL AUTO_INCREMENT,
 	    `username` VARCHAR(64) NULL DEFAULT NULL,
 	    `departname` VARCHAR(64) NULL DEFAULT NULL,
 	    `created` DATE NULL DEFAULT NULL,
 	    PRIMARY KEY (`uid`)
 	);
-	
+```	
 The following example shows how to operate on a database based on the `database/sql` interface standards.
-
+```Go
 	package main
 
 	import (
@@ -102,7 +102,7 @@ The following example shows how to operate on a database based on the `database/
 	        panic(err)
 	    }
 	}
-
+```
 Let me explain a few of the important functions here:
 
 - `sql.Open()` opens a registered database driver. The Go-MySQL-Driver registered the mysql driver here. The second argument is the DSN (Data Source Name) that defines information pertaining to the database connection. It supports following formats:

en/05.3.md

@@ -15,16 +15,16 @@ The first driver is the only one that supports the `database/sql` interface stan
 ## Samples
 
 We create the following SQL:
-
+```sql
 	CREATE TABLE `userinfo` (
 	    `uid` INTEGER PRIMARY KEY AUTOINCREMENT,
 	    `username` VARCHAR(64) NULL,
 	    `departname` VARCHAR(64) NULL,
 	    `created` DATE NULL
 	);
-
+```
 An example:
-
+```Go
 	package main
 
 	import (
@@ -101,11 +101,11 @@ An example:
 	        panic(err)
 	    }
 	}
-
+```
 You may have noticed that the code is almost the same as in the previous section, and that we only changed the name of the registered driver and called `sql.Open` to connect to SQLite in a different way.
 
 Note that sometimes you can't use the `for` statement because you don't have more than one row, then you can use the `if` statement
-
+```Go
     if rows.Next() {
         err = rows.Scan(&uid, &username, &department, &created)
         checkErr(err)
@@ -114,14 +114,14 @@ Note that sometimes you can't use the `for` statement because you don't have mor
         fmt.Println(department)
         fmt.Println(created)
     }
-
+```
 Also you have to do a `rows.Next()`, without using that you can't fetch data in the `Scan` function.
 
 Transactions
 ===============
 
 The above example shows how you fetch data from the database, but when you want to write a web application then it will not only be necessary to fetch data from the db but it will also be required to write data into it. For that purpose, you should use transactions because for various reasons, such as having multiple go routines which access the database, the database might get locked. This is undesirable in your web application and the use of transactions is effective in ensuring your database activities either pass or fail completely depending on circumstances. It is clear that using transactions can prevent a lot of things from going wrong with the web app.
-
+```Go
     trashSQL, err := database.Prepare("update task set is_deleted='Y',last_modified_at=datetime() where id=?")
     if err != nil {
         fmt.Println(err)
@@ -137,7 +137,7 @@ The above example shows how you fetch data from the database, but when you want
     } else {
     	tx.Commit()
     }
-    
+```    
 As it is clear from the above block of code, you first prepare a statement, after which you execute it, depending on the output of that execution then you either roll it back or commit it.
 
 

en/05.4.md

@@ -15,7 +15,7 @@ I will use the first one in the examples that follow.
 ## Samples
 
 We create the following SQL:
-
+```sql
 	CREATE TABLE userinfo
 	(
 	    uid serial NOT NULL,
@@ -25,9 +25,9 @@ We create the following SQL:
 	    CONSTRAINT userinfo_pkey PRIMARY KEY (uid)
 	)
 	WITH (OIDS=FALSE);
-
+```
 An example:
-
+```Go
 	package main
 
 	import (
@@ -102,20 +102,20 @@ An example:
 			panic(err)
 		}
 	}
-
+```
 Note that PostgreSQL uses the `$1, $2` format instead of the `?` that MySQL uses, and it has a different DSN format in `sql.Open`. 
 Another thing is that the PostgreSQL driver does not support `sql.Result.LastInsertId()`.
 So instead of this,
-
+```Go
 	stmt, err := db.Prepare("INSERT INTO userinfo(username,departname,created) VALUES($1,$2,$3);")
 	res, err := stmt.Exec("astaxie", "研发部门", "2012-12-09")
 	fmt.Println(res.LastInsertId())
-
+```
 use `db.QueryRow()` and `.Scan()` to get the value for the last inserted id.
-
+```Go
 	err = db.QueryRow("INSERT INTO TABLE_NAME values($1) returning uid;",	VALUE1").Scan(&lastInsertId)
 	fmt.Println(lastInsertId)
-
+```
 ## Links
 
 - [Directory](preface.md)