- 浏览: 105628 次
- 性别:
- 来自: 厦门
文章分类
最新评论
-
u011404046:
又是这种坑人的代码,,这只是获取别人的定位信息而已,如果get ...
Android GPS定位 -
pulove:
很好,YEYE
Android GPS定位 -
jianai115:
亲,看不懂啊,源代码可以发一下吗?1003862555@qq. ...
Android GPS定位
MySQL的预定义字符一直没有认真去研究过,结果前几天写数据库的时候出问题了……ORZ……如果要用这些字符,必须如下方法
CREATE TABLE `interval` (begin INT, end INT);
CREATE TABLE mydb.interval (begin INT, end INT);
创建表格的时候系统没有报错,但是做SQL语句查询的时候问题来了,一查才知道,是因为用了div做column的名字,而自己不知道这是MySQL的预定义字符。决定花点时间,好好学习一下,不能再犯类似的错误了。
ADD : 修改表结构时用于添加column
ALL: 用在查询的判断中https://dev.mysql.com/doc/refman/5.5/en/all-subqueries.html
ALTER: 修改表结构时使用
ANALYZE: 应该是用在数据库管理中analyze table -- analyzes and stores the key distribution for a table。http://dev.mysql.com/doc/refman/5.6/en/analyze-table.html
AND: 判断时常用
AS: 选择时常用
ASC: 排序使用,顺序排列。不过mysql默认的排序就是ASC,可以不写。
ASENSITIVE: Google翻译,这个词的意思是敏感性未定型。从MySQL的官方文档看,这是Mysql 5的预定义字符,但是这个字符做什么用,我没有找到相关文档╮(╯_╰)╭。
BEFORE: 用于出发预定义的程序,与trigger一起用,是在某操作事件发生前,触发
BETWEEN:用在条件判断中,用来替换 <= and >=,可以这样写 where t1 between '2012-01-01' and '2012-06-01'
BIGINT: 8 byte integer
BINARY: is an operator casts the string following it to a binary string
BLOB: a binary large object that can hold a variable amount of data. 与TEXT相对应的。用比特流来存储数据
BOTH: mysql> SELECT TRIM(BOTH 'x' FROM 'xxxbarxxx');
-> 'bar'
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html
BY: order by columnX
CALL:invokes a stored procedure that was defined previously with CREATE PROCEDURE
. http://dev.mysql.com/doc/refman/5.5/en/call.html
CASCADE:a reference option, Delete or update the row from the parent table, and automatically delete or update the matching rows in the child table. http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html
CASE:用法很像其他编程语言里的switch(){ case:....}
http://dev.mysql.com/doc/refman/5.0/en/case-statement.html
CHANGE: 有个命令叫 change master to [option,...] http://dev.mysql.com/doc/refman/5.0/en/change-master-to.html
CHAR:相对于varchar来说,存储占用空间不变长度,需要一提的是,char(4)占用4bytes,而varchar(4)在4个字符存满的情况下,占用5bytes。http://dev.mysql.com/doc/refman/5.0/en/char.html
CHARACTER:用于对CHARACTER SET操作
CHECK: 有check table 命令,检查table的状态和错误http://dev.mysql.com/doc/refman/5.0/en/check-table.html
COLLATE:覆盖原字码的字符编码,可以用在比对中如果存在特殊字符的情况下http://dev.mysql.com/doc/refman/5.0/en/charset-collate.html
COLUMN:常用,不解释
CONDITION: 没找到,在文档中提到condition的时候,指的是判断的条件语句 when [condtion],不过似乎本身并没有这个命令。
CONNECTION: KILL CONNECTION = KILL ,类似的还有KILL QUERY,用于切断链接或者正在查询中的语句http://dev.mysql.com/doc/refman/5.1/en/kill.html
CONSTRAINT:
The CONSTRAINT
clause allows you to name the constraint explicitly, either to make metadata more readable or else to use the name when you want to drop the constraint. The SQL standard requires that the CONSTRAINT
clause is optional. If you leave it out, the RDBMS creates a name automatically, and the name is up to the implementation. http://stackoverflow.com/questions/310561/mysql-terminology-constraints-vs-foreign-keys-difference
CONTINUE:有点像其它语言里循环的时候用的continue http://dev.mysql.com/doc/refman/5.0/en/declare-handler.html
CONVERT:字符编码转换 http://dev.mysql.com/doc/refman/5.0/en/charset-convert.html
CREATE:常用,不解释
CROSS: 在MYSQL中 JOIN = CROSS JOIN = INNER JOIN http://miyulano.iteye.com/admin/blogs/1164659
CURRENT_DATE: 等同于 CURDATE()
CURRENT_TIME:等同于
CURTIME()
CURRENT_TIMESTAMP:等同于 NOW()
CURRENT_USER: return currentuser@hostname
CURSOR:
http://dev.mysql.com/doc/refman/5.0/en/cursors.html
DATABASE: 字面意思,不解释
DATABASES: 最常用的大概是show databases
DAY_HOUR, DAY_MICROSECOND, DAY_MINUTE, DAY_SECOND: http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html
DEC: 十进制 DEC = DECIMAL = FIXED
DECIMAL: 十进制 DEC = DECIMAL = FIXED
DECLARE:
The DECLARE
statement is used to define various items local to a program http://dev.mysql.com/doc/refman/5.0/en/declare.html
DEFAULT: 常用,不解释
DELAYED: INSERT DELAYED, 感觉是先写在缓存中,积累到一定量一次写入disk中?http://dev.mysql.com/doc/refman/5.5/en/insert-delayed.html
DELETE: 常用,不解释
DESC: 倒序排序
DESCRIBE: DESCRIBE {tablename} = DESC {tablename}
DETERMINISTIC:
http://dev.mysql.com/doc/refman/5.1/en/stored-programs-logging.html
DISTINCT: 用在select中,有order by的作用http://dev.mysql.com/doc/refman/5.0/en/distinct-optimization.html
DISTINCTROW: The ALL
and DISTINCT
options specify whether duplicate rows should be returned. ALL
(the default) specifies that all matching rows should be returned, including duplicates. DISTINCT
specifies removal of duplicate rows from the result set. It is an error to specify both options. DISTINCTROW
is a synonym for DISTINCT
. http://dev.mysql.com/doc/refman/5.5/en/select.html
DIV: Integer division (整数除法)http://dev.mysql.com/doc/refman/5.0/en/arithmetic-functions.html
DOUBLE: 常用,不解释
DROP: 常用,不解释
DUAL: You are permitted to specify DUAL
as a dummy table name in situations where no tables are referenced
EACH:没找到╮(╯_╰)╭
ELSE,ELSEIF:同其他语言
ENCLOSED:FIELDS的选项for LOAD DATA, controls how to read or write special characters
ESCAPED:同上http://dev.mysql.com/doc/refman/5.1/en/load-data.html
EXISTS:If a subquery returns any rows at all, EXISTS
is subquery
TRUE
, and NOT EXISTS
is subquery
FALSE
. http://dev.mysql.com/doc/refman/5.0/en/exists-and-not-exists-subqueries.html
EXIT:Command,Exit mysql. Same as quit.
EXPLAIN:The EXPLAIN
statement can be used either as a way to obtain information about how MySQL executes a statement, or as a synonym for DESCRIBE
: http://dev.mysql.com/doc/refman/5.0/en/explain.html
FALSE:常用,不解释
FETCH: 类似mysql_fetch_array这样的,http://dev.mysql.com/doc/refman/5.0/en/fetch.html,http://dev.mysql.com/doc/refman/5.0/en/cursors.html
FLOAT:数据类型,长度4字节 详细:http://www.5iphp.com/node/140
FLOAT4, FLOAT8: MySQL allows FLOAT4 and FLOAT8 as synonyms, but what they are synonyms for depends on your version of MySQL:
-
Prior to MySQL 3.23.6, FLOAT4 and FLOAT8 are equivalent to FLOAT(10,2) and DOUBLE(16,4).
-
For MySQL 3.23.6 and later, FLOAT4 and FLOAT8 are equivalent to FLOAT and DOUBLE.
FOR: (没找到相关)
FORCE:{USE|FORCE} INDEX
is applied if present. (If not, the optimizer-determined set of indexes is used.) http://dev.mysql.com/doc/refman/5.1/en/index-hints.html
FOREIGN: foreign key
FROM: 常用,不解释
FULLTEXT:an index type, the more words in the text, the large size of the index, more: http://dev.mysql.com/doc/refman/5.0/en/fulltext-search.html
GOTO: 编程语言里常见
GRANT: grant user privileges
GROUP: 常用
HAVING:用来约束group by http://dev.mysql.com/doc/refman/5.0/en/group-by-hidden-columns.html
HIGH_PRIORITY:HIGH_PRIORITY
gives the SELECT
higher priority than a statement that updates a table. You should use this only for queries that are very fast and must be done at once. HIGH_PRIORITY
cannot be used with SELECT
statements that are part of a UNION
.http://dev.mysql.com/doc/refman/5.5/en/select.html
HOUR_MICROSECOND: format 'HOURS:MINUTES:SECONDS.MICROSECONDS'
HOUR_MINUTE: format 'HOURS:MINUTES'
HOUR_SECOND: format 'HOURS:MINUTES:SECONDS'
IF: 判断
IGNORE: IGNORE INDEX
IN: Where a in ( x, x, x)
INDEX: 索引http://database.51cto.com/art/201010/229475.htm
INFILE: load data infile http://dev.mysql.com/doc/refman/5.1/en/load-data.html
INNER: inner join
INOUT: 执行前需要被初始化的全局变量http://dev.mysql.com/doc/refman/5.0/en/call.html
INSENSITIVE:与string的匹配相关
INSERT: 常用,不解释
INT:4字节
INT1 : = TINYINT 1字节 (-128 ~ 127 | 0 - 255)
INT2 = Small 2字节(-32768 ~ 32767 | 0 ~ 65535)
INT3 = MEDIUMINT 3字节 (1600万+)
INT4 = INT 4字节 (40亿+)
INT8 = BIGINT 8字节
INTEGER = INT
INTERVAL: 用在时间相关的函数里。The INTERVAL
keyword and the unit
specifier are not case sensitive. http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html
INTO: insert into table
IS: is null, is not null. http://dev.mysql.com/doc/refman/5.0/en/working-with-null.html
ITERATE: means “start the loop again.” http://dev.mysql.com/doc/refman/5.0/en/iterate-statement.html
JOIN: 常用,不解释
KEY:
KEY is normally a synonym for INDEX. The key attribute PRIMARY KEY can also be specified as just KEY when given in a column definition.
http://stackoverflow.com/questions/924265/what-does-the-key-keyword-mean
KEYS: (╮(╯_╰)╭)
KILL: Each connection to mysqld runs in a separate thread. You can see which threads are running with the SHOW PROCESSLIST
statement and kill a thread with the KILL
statement. http://dev.mysql.com/doc/refman/5.0/en/kill.html thread_id
LABEL: 用来标记loop
http://dev.mysql.com/doc/refman/5.1/en/statement-labels.html
LEADING:mysql> SELECT TRIM(LEADING 'x' FROM 'xxxbarxxx');
-> 'barxxx'
http://dev.mysql.com/doc/refman/5.0/en/string-functions.html
LEAVE: LEAVE label
This statement is used to exit the flow control construct that has the given label. If the label is for the outermost stored program block, LEAVE
exits the program.
http://dev.mysql.com/doc/refman/5.0/en/leave-statement.html
LEFT: 常用 left join
LIKE:常用 like '%%s%'
LIMIT: 常用
LINEAR:
linear hashing
http://dev.mysql.com/doc/refman/5.1/en/partitioning-linear-hash.html
LINES: load data infile 中,用于定义line的起始 http://dev.mysql.com/doc/refman/5.1/en/load-data.html
LOAD:load data infile http://dev.mysql.com/doc/refman/5.1/en/load-data.html
LOCALTIME:等同于
NOW()
LOCALTIMESTAMP:等同于NOW()
LOCK: lock table http://dev.mysql.com/doc/refman/5.0/en/lock-tables.html
LONG:在mysql中相当于
MEDIUMTEXT 长度是
L
+ 3 bytes, where L
< 224
LONGBLOB:二进制方式存储的LONG,用于存放可变的数据,长度
L
+ 4 bytes, where L
< 232
LONGTEXT: L
+ 4 bytes, where L
< 232
LOOP: 循环
LOW_PRIORITY:To give a specific INSERT
, UPDATE
, or DELETE
statement lower priority, use the LOW_PRIORITY
attribute.http://dev.mysql.com/doc/refman/5.0/en/table-locking.html
MATCH:
MATCH (
感觉像精确搜索,查找COL1,COL2中是否有匹配的的字段,但是,当匹配字段的出现率在表中高于50%时,返回结果为0 http://dev.mysql.com/doc/refman/5.0/en/fulltext-natural-language.html col1
,col2
,...) AGAINST (expr
[search_modifier
])
MEDIUMBLOB:
A BLOB
is a binary large object that can hold a variable amount of data. The four BLOB
types are TINYBLOB
, BLOB
,MEDIUMBLOB
. 长度等同于MEDIUMTEXT,都是L
+ 3 bytes, where L
< 224http://dev.mysql.com/doc/refman/5.0/en/blob.html
MEDIUMINT:3byte长的int,(+-)800 0000+
MEDIUMTEXT:L
+ 3 bytes, where L
< 224
MIDDLEINT: 在网络上找到的说法是mysql 没有
MIDDLEINT 这个数据类型,但是它的确在预定义词组里╮(╯_╰)╭
MINUTE_MICROSECOND: fomate 'MINUTES:SECONDS.MICROSECONDS'http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html
MINUTE_SECOND: fomate 'MINUTES:SECONDS' http://dev.mysql.com/doc/refman/5.5/en/date-and-time-functions.html
MOD: 求余数,等同于%(Modulo operation. Returns the remainder of N
divided by M
)
MODIFIES: MODIFIES SQL DATA
indicates that the routine contains statements that may write data (for example, INSERT
orDELETE
) http://dev.mysql.com/doc/refman/5.0/en/create-procedure.html
NATURAL : The NATURAL [LEFT] JOIN
of two tables is defined to be semantically equivalent to an INNER JOIN
or a LEFT JOIN
with a USING
clause that names all columns that exist in both tables.
NOT:常用
NO_WRITE_TO_BINLOG: By default, the server writes FLUSH
statements to the binary log so that they replicate to replication slaves. To suppress logging, use the optional NO_WRITE_TO_BINLOG
keyword or its alias LOCAL
.
NULL:常用
NUMERIC: ╮(╯_╰)╭numeric functions
http://dev.mysql.com/doc/refman/5.0/en/numeric-functions.html
ON:和join一起用
OPTIMIZE:For InnoDB
tables, OPTIMIZE TABLE
is mapped to ALTER TABLE
, which rebuilds the table to update index statistics and free unused space in the clustered index.http://dev.mysql.com/doc/refman/5.1/en/optimize-table.html
OPTION: ╮(╯_╰)╭
OPTIONALLY: If you specify OPTIONALLY
, the ENCLOSED BY
character is used only to enclose values from columns that have a string data type (such as CHAR
, BINARY
, TEXT
, or ENUM
): http://dev.mysql.com/doc/refman/5.0/en/load-data.html
OR:常用 where中
ORDER:常用
OUT: 三种类型的变量,in是局部变量,传值不传参,out为全局变量,但初始化时值必须为NULL,inout也是全局,但是通过传值来设置初始值。
OUTER: 外链接 outer join
OUTFILE: SELECT ... INTO OUTFILE
writes the selected rows to a file.
PRECISION: 精密匹配?
PRIMARY:primary key
PROCEDURE:CREATE PROCEDURE, it can be called later
http://dev.mysql.com/doc/refman/5.0/en/create-procedure.html
PURGE:清除logThe PURGE BINARY LOGS
statement deletes all the binary log files listed in the log index file prior to the specified log file name or date. http://dev.mysql.com/doc/refman/5.0/en/purge-binary-logs.html
RAID0: RAID是一种存储技术http://en.wikipedia.org/wiki/RAID, 按照我的理解,RAID 0应该是相对于操作系统层的和存储相关的命名。它不是一个专有名词,而是约定熟成的RAID的某个scheme。
RANGE:
READ:
READS :
REAL:相当于DOUBLE PRECISION
REFERENCES:定义foreign key时使用
REGEXP:用于正则表达式匹配字符串
http://dev.mysql.com/doc/refman/5.1/en/regexp.html#operator_regexp
RELEASE:
RENAME :修改表名、数据库名的时候用
REPEAT: 重复。。直到。。REPEAT...UNITL...END REPEAT
http://dev.mysql.com/doc/refman/5.0/en/repeat-statement.html
REPLACE:1, REPLACE
works exactly like INSERT
, except that if an old row in the table has the same value as a new row for aPRIMARY KEY
or a UNIQUE
index, the old row is deleted before the new row is inserted. 2, REPLACE(text_string, from_string, to_string)。
REQUIRE : 用在GRANT中,用于限定用户,比如REQUIRE SSL
http://dev.mysql.com/doc/refman/5.0/en/grant.html
RESTRICT: a reference option, Rejects the delete or update operation for the parent table. http://dev.mysql.com/doc/refman/5.5/en/innodb-foreign-key-constraints.html
RETURN: 就是你想到的那个常用意思。
REVOKE: REVOKE语句允许系统管理员从MySQL账户撤销的特权。E.G. REVOKE INSERT ON *.* FROM 'jeffrey'@'localhost'; http://dev.mysql.com/doc/refman/4.1/en/revoke.html
RIGHT:1,right join; 2 ,从右边开始截取字符串
RLIKE:Synonym for REGEXP 用正则表达式匹配
SCHEMA: CREATE SCHEMA is a synonym for CREATE DATABASE as of MySQL 5.0.2.
SCHEMAS: SHOW SCHEMAS等同于SHOW DATABASES
SECOND_MICROSECOND:
SELECT DATE_ADD('1992-12-31 23:59:59.000002',
INTERVAL '1.999999' SECOND_MICROSECOND);
SELECT:常用
SENSITIVE:
SEPARATOR:在GROUP_CONCAT中使用,这个function的作用是将查询到的记录合并成一个string, separator来定义分隔字符。http://mahmudahsan.wordpress.com/2008/08/27/mysql-the-group_concat-function/
SET: 常用
SHOW: 常用http://dev.mysql.com/doc/refman/5.5/en/show.html
SMALLINT:The signed range is –32768 to 32767.
SPATIAL: 用于定义index http://dev.mysql.com/doc/refman/5.0/en/create-index.html
SPECIFIC:
SQL:
SQLEXCEPTION:SQLEXCEPTION
is shorthand for the class of SQLSTATE values that do not begin with '00'
, '01'
, or '02'
. http://dev.mysql.com/doc/refman/5.1/en/declare-handler.html
SQLSTATE: 看上一条。
SQLWARNING:SQLWARNING
is shorthand for the class of SQLSTATE values that begin with '01'
SQL_BIG_RESULT: SQL_BIG_RESULT
or SQL_SMALL_RESULT
can be used with GROUP BY
or DISTINCT
to tell the optimizer that the result set has many rows or is small, respectively. For SQL_BIG_RESULT
, MySQL directly uses disk-based temporary tables if needed, and prefers sorting to using a temporary table with a key on the GROUP BY
elements. For SQL_SMALL_RESULT
, MySQL uses fast temporary tables to store the resulting table instead of using sorting. This should not normally be needed. http://dev.mysql.com/doc/refman/5.1/en/select.html
SQL_CALC_FOUND_ROWS: SQL_CALC_FOUND_ROWS
tells MySQL to calculate how many rows there would be in the result set, disregarding any LIMIT
clause. SQL_CALC_FOUND_ROWS
and FOUND_ROWS()
can be useful in situations when you want to restrict the number of rows that a query returns, but also determine the number of rows in the full result set without running the query again. http://dev.mysql.com/doc/refman/5.5/en/information-functions.html
SQL_SMALL_RESULT:http://dev.mysql.com/doc/refman/5.1/en/select.html
SSL:就是你知道的那个SSL
STARTING:
STRAIGHT_JOIN:STRAIGHT_JOIN
is similar to JOIN
, except that the left table is always read before the right table.
TABLE:常用
TERMINATED:
例子:
SELECT * INTO OUTFILE 'data.txt'
FIELDS TERMINATED BY ','
FROM table2;
THEN:WHEN...THEN
TINYBLOB:L
+ 1 bytes, where L
< 28
TINYINT: -128 ~ 127
TINYTEXT:L
+ 1 bytes, where L
< 28
TO:
TRAILING: TRIM([{BOTH | LEADING | TRAILING} [remstr] FROM ] str), Indicates that only trailing prefixes are to be removed.
TRIGGER:A trigger is a named database object that is associated with a table, and that activates when a particular event occurs for the table.
TRUE:你懂的
UNDO:这个.....
UNION:UNION
is used to combine the result from multiple SELECT
statements into a single result set.
UNIQUE : 你懂的
UNLOCK: UNLOCK TABLE http://dev.mysql.com/doc/refman/5.0/en/lock-tables.html
UNSIGNED:用于非负数定义
UPDATE:你懂的
USAGE: Synonym for “no privileges”。 USAGE
can be specified to create a user that has no privileges, or to specify the REQUIRE
or WITH
clauses for an account without changing its existing privileges.
USE: use database_name
USING:The USING(
clause names a list of columns that must exist in both tables. If tables column_list
)a
and b
both contain columns c1
, c2
, and c3
, the following join compares corresponding columns from the two tables:
a LEFT JOIN b USING (c1,c2,c3)
http://dev.mysql.com/doc/refman/5.0/en/join.html
UTC_DATE: UTC - 世界标准时间 return 'YYYY-MM-DD'
UTC_TIME: returns the current UTC time as a value in 'HH:MM:SS' or HHMMSS format depending on the context of the function
UTC_TIMESTAMP: return 'YYYY-MM-DD HH:MM:SS'
VALUES: 你懂的
VARBINARY:The BINARY
and VARBINARY
types are similar to CHAR
and VARCHAR
, except that they contain binary strings rather than nonbinary strings.
VARCHAR:你懂的
VARCHARACTER: 貌似没有
VARYING:VARCHAR是CHARACTER VARYING一个缩写
WHEN:你懂的
WHERE :你懂的
WHILE:循环,你懂的
WITH: 据说 WITH AS 用于缩短select时间,但是没在MYSQL上找到相关文档
WRITE:
X509: GRANT数据库操作权限给用户的时候,REQUIRE的选项,和SSL相似
XOR: Logical XOR. Returns NULL
if either operand is NULL
. For non-NULL
operands, evaluates to 1
if an odd number of operands is nonzero, otherwise 0
is returned.
http://dev.mysql.com/doc/refman/5.0/en/logical-operators.html
YEAR_MONTH:
SELECT EXTRACT(YEAR_MONTH FROM '2009-07-02 01:02:03');
-> 200907
ZEROFILL: 等同于 UNSIGNED。If you specify ZEROFILL
for a numeric column, MySQL automatically adds the UNSIGNED
attribute to the column.
发表评论
-
PHP查询MySQl数据库的效率小记
2012-11-18 13:24 8711. MySQL数据库的连接和 ... -
关于float的精准问题原因
2012-07-16 21:34 797最近在整理关于MYSQL预定义词的笔记,然后发现了一个经常被提 ... -
MySQL中JOIN到用法
2011-09-02 21:15 855- LEFT JOIN FROM a LEFT JOI ... -
Postgresql 数据库使用笔记
2011-08-05 11:51 555安装: $ sudo apt-get install p ... -
不同数据库SQL语句的差别
2011-06-20 21:44 10621,系统时间 Oracle:SYSDATE SQLSe ...
相关推荐
2.3.2 预定义变量 2.3.3 变量作用域 2.3.4 可变变量 2.4 常量 2.4.1 自定义常量 2.4.2 魔术常量 2.5 表达式 2.6 运算符 2.6.1 算术运算符 2.6.2 字符串运算符 2.6.3 比较运算符 2.6.4 逻辑运算符 2.6.5 ...
基本概念 • 字符(Character)是指人类语言中最小的表义符号。例如’A’、’B’等; • 给定一系列字符,对每个字符赋予一个数值,用数值来代表对应的字符,这一数值就是字符的编码(Encoding)。例如,我们给字符’A’...
所以,应该使用mysql_real_escape_string函数: mysql_real_escape_string — 转义 SQL 语句中使用的字符串中的特殊字符,并考虑到连接的当前字符集。 但是注意:该函数并不转义 % 和 _。另外,最好不要对整条sql...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
PHP内置丰富的数据类型(如整型、浮点型、字符串、数组、对象等),并提供了大量的预定义函数,涵盖了字符串操作、数学运算、文件系统处理、日期时间处理、数据库连接等常见功能,极大提高了开发效率。 在Web开发中...
本文实例总结了MySQL数据库常用操作技巧。分享给大家供大家参考,具体如下: 一、查询不同表中同名字段(表连接查询条件神器) ...预定义变量: /*错误代码*/ SET @RetCode='1'; /*错误提示*/ SET @
程序员5个刷题网站 电商数据库设计及架构优化实战 ...所有数据库对象名称必须要见名识义,并且最好不超过32个字符 临时表:以 tmp 为前缀并以日期为后缀 备份表:以 bak 为前缀并以日期为后缀 所有存储相同数据的
CONNECT, RESOURCE, DBA这些预定义角色主要是为了向后兼容。其主要是用于数据库管理。oracle建议用户自己设计数据库管理和安全的权限规划,而不要简单的使用这些预定角色。将来的版本中这些角色可能不会作为预定...
术、SQL查询相关技术、MySQL高级应用技术、字符串的处理技术、PHP面向对象编程技术、文件管理、图像和多媒体技术、信息提取与图表分析 技术、报表与打印技术、网络通信技术、PHP与XML技术、安全技术、PHP高级应用...
预定义变量 37 函数 39 数组 40 一.用字符串做下标 40 二.使用小数作为key将,自动截断小数部分 40 四.删除数组元素 40 六.二维数组。 40 类 41 一.重载 41 二.覆盖 41 三.抽象类 41 四.final 42 五....