127.0.0.1:6379> PING PONG 但是， 如果⽤户给定了可选的消息， 那么服务器将原封不动地向客户端返回该消息： 127.0.0.1:6379> PING "hello world" "hello world" 另⼀⽅⾯， 如果服务器与客户端的连接不正常， 那么客户端将返回⼀个错误： -- 客户端未能连接服务器，返回⼀个连接错误 127.0.0.1:6379> PING 被关联的键和值既可以是普通的⽂字数据， 也可以是图⽚、视频、⾳频、压缩⽂件等更为复杂的⼆进制数 据。 作为例⼦， 图 2-1 展示了数据库视⻆下的四个字符串键， 其中： 与键 "message" 相关联的值是 "hello world" ； 与键 "number" 相关联的值是 "10086" ； 与键 "homepage" 相关联的值是 "redis.io" ； 与键 "redis-logo.jpg" 相关联的值是⼆进制数据 命令接受⼀个字符串键作为参数， 然后返回与该键相关联的值。 ⽐如对于图 2-4 所示的数据库来说， 我们可以通过执⾏以下 GET 命令来取得各个字符串键相关联的值： redis> GET message "hello world" redis> GET number "10086" redis> GET homepage "redis.io" 图 2-4 使⽤ GET 命令获取数据库键的值 另⼀⽅⾯，

текстовые блобы (BLOB) любой размерности и с любым набором символов. Примеры: SELECT BIT_LENGTH('Hello!') FROM RDB$DATABASE -- возвращает 48 SELECT BIT_LENGTH(_ISO8859_1 'Grüß Di!') FROM RDB$DATABASE обработку полей типа BLOB любой длины и с любым набором символов. Пример: SELECT CHAR_LENGTH('Hello!') FROM RDB$DATABASE -- Результат 6 SELECT CHAR_LENGTH(_ISO8859_1 'Grüß di!') FROM RDB$DATABASE версиях. Примеры: LPAD ('Hello', 12) -- Результат: ' Hello' LPAD ('Hello', 12, '-') -- Результат: '-------Hello' LPAD ('Hello', 12, '') -- Результат: 'Hello' LPAD ('Hello', 12, 'abc') -- Результат:

операцию RIGHT TRIM. Примеры: Пример 7.29. Использование функции BIT_LENGTH SELECT BIT_LENGTH ('Hello!') FROM RDB$DATABASE -- возвращает 48 SELECT BIT_LENGTH (_ISO8859_1 'Grüß Di!') FROM RDB$DATABASE LPAD ('Hello', 12) -- возвращает ' Hello' LPAD ('Hello', 12, '-') -- возвращает '-------Hello' LPAD ('Hello', 12, '') -- возвращает 'Hello' LPAD ('Hello', 12, 'abc') 'abcabcaHello' LPAD ('Hello', 12, 'abcdefghij') -- возвращает 'abcdefgHello' LPAD ('Hello', 2) -- возвращает 'He' LPAD ('Hello', 2, '-') -- возвращает 'He' LPAD ('Hello', 2, '')

function fully supports text BLOBs of any length and character set. Examples select bit_length('Hello!') from rdb$database -- returns 48 select bit_length(_iso8859_1 'Grüß di!') from rdb$database -- function fully supports text BLOBs of any length and character set. Examples select char_length('Hello!') from rdb$database -- returns 6 select char_length(_iso8859_1 'Grüß di!') from rdb$database -- Examples lpad ('Hello', 12) -- returns ' Hello' lpad ('Hello', 12, '-') -- returns '-------Hello' lpad ('Hello', 12, '') -- returns 'Hello' lpad ('Hello', 12, 'abc')

fully supports text BLOBs of any length and character set. BIT_LENGTH Examples select bit_length('Hello!') from rdb$database -- returns 48 select bit_length(_iso8859_1 'Grüß di!') from rdb$database -- from the 2nd argument into it Chapter 8. Built-in Scalar Functions 437 b = blob_append(null, 'Hello '); -- adds two strings to the temporary BLOB without closing it b = blob_append(b, 'World', -- comparing a BLOB with a string will close it, because the BLOB needs to be read if (b = 'Hello World!') then begin -- ... end -- creates a temporary closed BLOB by adding a string to it

Text-BLOBs jeder Länge und jedes beliebigen Zeichensatzes. BIT_LENGTH-Beispiele select bit_length('Hello!') from rdb$database -- Ergebnis 48 select bit_length(_iso8859_1 'Grüß di!') from rdb$database -- Text-BLOBs jeder Länge und jedes beliebigen Zeichensatzes. CHAR_LENGTH-Beispiele select char_length('Hello!') from rdb$database -- Ergebnis 6 select char_length(_iso8859_1 'Grüß di!') from rdb$database -- LPAD-Beispiele lpad ('Hello', 12) -- Ergebnis ' Hello' lpad ('Hello', 12, '-') -- Ergebnis '-------Hello' lpad ('Hello', 12, '') -- Ergebnis 'Hello' lpad ('Hello', 12, 'abc')

mysql>> select select rpad rpad(("hello" "hello",, 10 10,, 'xy' 'xy'));; ++-------------------------+ -------------------------+ || rpad rpad(('hello' 'hello',, 10 10,, 'xy' 'xy')) || ++- --------------| |---------|---------|--------------| | Pete | USA | Hello | | Pete | USA | Hello | | John | USA | Hi | | John | USA | Hi || || USA USA || John John || Hello Hello || || USA USA || Pete Pete || Hello Hello || Baidu 百度智能云文档 SQL手册 199 用来计算当前行向前数若干行的值。

The following statement will fail with a constraint violation, because 'hello' is not an integer: INSERT INTO bar (a) VALUES ('hello'); 3.7. Limitations of SQLite virtual tables There are a few features database, which contains the following row: INSERT INTO foo (a) VALUES ('hello'); • Harold does: INSERT INTO bar (b) VALUES ('hello'); • Don does: DELETE FROM foo; • Don does: SELECT zumero_sync(.. declare column x this way, you can omit x from an INSERT statement: INSERT INTO foo (y) VALUES ('hello'); and column x will automatically get an integer value which is one greater than the largest value

message_.ParseFromArray(rbuf_ + cur_pos_ - header_len_, header_len_); message_.set_name("hello " + message_.name()); uint32_t u =htonl( message_.ByteSize()); memcpy(static_cast(wbuf_) com/Qihoo360/nemo SACC2017 存储引擎--Nemo SACC2017 • HSET myhash field1 "Hello" – DB->Put(wop, h6myhashfield1,Hello01477671118) – DB->Put(wop, Hmyhash11477671118, 6) 存储引擎--Nemo SACC2017 存储引擎--Nemo

%s %s", "foo", "hello world"); printf("SET: %s\n", reply->str); freeReplyObject(reply); /* Set a key using binary safe API */ reply = redisCommand(c,"SET %b %b", "bar", (size_t) 3, "hello", (size_t) 5); 快速入门 22 SortedSet 开头代表5种数据结构。 string： hash list //set get string strKey = "hello"; string strValue = "world"; bool setResult = db.StringSet(strKey, strValue); Console.WriteLine("set