心得-MYH
我的MYSQL学习心得
我的MYSQL学习心得我的mysql学习心得（十六）优化一步一步走来已经写到了第十六篇了~这一篇主要介绍mysql的优化,优化mysql数据库是dba和开发人员的必备技能mysql优化一方面是找出系统瓶颈,提高mysql数据库整体性能；另一方面需要合理的结构设计和参数调整,以提高用户操作响应的速度；同时还有尽可能节省系统资源,以便系统可以提供更大负荷的服务如果大家看过我写的两篇文章,那么学习mysql的索引就不会太难,因为是相通的其实mysql也有sqlserver堆表的概念myisam允许没有任何索引和主键的表存在,个人觉得没有主键的myisam表都属于堆表,因为mysql不支持非主键的聚集索引.innodb引擎如果没有设定主键或者非空唯一索引,就会自动生成一个6字节的主键(用户不可见)详细参考:不过《myisamvsinnodb:mysql存储引擎详解》文章也有一点错误,意向共享锁就是表锁,其实是不对的1、优化简介mysql优化是多方面的,原则是减少系统的瓶颈,减少资源的占用,增加系统的反应速度.例如,通过优化文件系统,提高磁盘i/o的读写速度；通过优化操作系统调度策略,提高mysql在高负荷情况下的负载能力；优化表结构、索引、查询语句等使查询响应更快在mysql中,可以使用showstatus语句查询一些mysql的性能参数showstatuslike"value";其中value是要查询的参数值,一些常用性能参数如下:connections:连接mysql服务器的次数uptime:mysql服务器的上线时间slow_queries:慢查询的次数com_select:查询操作次数com_insert:插入操作次数com_update:更新操作次数com_delete:删除操作次数如果查询mysql服务器的连接次数,可以执行如下语句showstatuslike"connections";如果查询mysql服务器的慢查询次数,可以执行如下语句showstatuslike"slow_queries";2、优化查询查询是数据库最频繁的操作,提高查询速度可以有效地提高mysql数据库的性能（1）分析查询语句通过对查询语句的分析,可以了解查询语句的执行情况找出查询语句执行的瓶颈mysql中提供了explain语句和describe语句,用来分析查询语句explain语句的基本语法explain[extended]selectselect_option使用extended关键字,explain语句将产生附加信息.select_option是select语句的查询选项,包括fromwhere子句等执行该语句,可以分析explain后面的select语句的执行情况,并且能够分析所查询的表的一些特征使用explain语句来分析1个查询语句usetest;explainextendedselect*fromperson;下面对结果进行解释·idselect识别符.这是select的查询序列号.·select_typeselect类型,可以为以下任何一种:simple:简单select(不使用union或子查询)primary:表示主查询,或者是最外层的查询语句（多表连接的时候）union:表示连接查询的第二个或后面的查询语句dependentunion:union连接查询中的第二个或后面的select语句,取决于外面的查询unionresult:union连接查询的结果subquery:子查询中的第一个select语句dependentsubquery:子查询中的第一个select语句,取决于外面的查询derived:导出表的select(from子句的子查询)·table表示查询的表·type表示表的联接类型下面给出各种联接类型,按照从最佳类型到最坏类型进行排序:（1）system表仅有一行(=系统表).这是const联接类型的一个特例.（2）const表最多只有一个匹配行,它将在查询开始时被读取.余下的查询优化中被作为常量对待.const表查询速度很快,因为它们只读取一次.const用于常数值比较primarykey或unique索引的所有部分的场合.在下面的查询中,tbl_name可以用于const表:（3）eq_ref对于每个来自于前面的表的行组合,从该表中读取一行.这可能是最好的联接类型,除了const类型.它用在一个索引的所有部分被联接使用并且索引是unique或primarykey时.eq_ref可以用于使用“=”操作符比较的带索引的列.比较值可以为常量或一个使用在该表前面所读取的表的列的表达式.在下面的例子中,mysql可以使用eq_ref联接来处理ref_tables:select*fromref_table,other_tablewhereref_table.key_colum n=other_table.column;select*fromref_table,other_tablewhereref_table.key_column_part1=other_table.columnandref_table.ke y_column_part2=1;（4）ref对于每个来自于前面的表的任意行组合,将从该表中读取所有匹配的行.如果联接只使用索引键的最左边的前缀,或如果索引键不是unique或primarykey,则使用ref.如果使用的键仅仅匹配少量行,该联接类型是不错的.ref可以用于使用=或<=>操作符的带索引的列.在下面的例子中,mysql可以使用ref联接来处理ref_tables:select*fromref_tablewherekey_column=expr;select*fromref_ table,other_tablewhereref_table.key_column=other_table.colu mn;select*fromref_table,other_tablewhereref_table.key_colum n_part1=other_table.columnandref_table.key_column_part2=1;（5）ref_or_null该联接类型如同ref,但是添加了mysql可以专门搜索包含null 值的行,在解决子查询中经常使用该联接类型的优化.在下面的例子中,mysql可以使用ref_or_null联接来处理ref_tables:select*fromref_tablewherekey_column=exprorkey_columnisnu ll;（6）index_merge该联接类型表示使用了索引合并优化方法.在这种情况下,key列包含了所用到的索引的清单,key_len列包含了所用到的索引的最长长度.（7）unique_subquery该类型替换了下面形式的in子查询的ref:valuein(selectprimary_keyfromsingle_tablewheresome_expr)unique_subquery是一个索引查找类型,可以完全替换子查询,效率更高.（8）index_subquery该联接类型类似于unique_subquery,不过索引类型不需要是唯一索引,可以替换in子查询,但只适合下列形式的子查询中的非唯一索引:valuein(selectkey_columnfromsingle_tablewheresome_expr)（9）range只检索给定范围的行,使用一个索引来检索行数据.key列显示使用了哪个索引,key_len显示所使用索引的长度.在该类型中ref列为null.当使用=、<>、>、>=、<、<=、isnull、<=>、between或者in 操作符,用常量比较关键字列时,类型为range.下面介绍几种检索指定行数据的情况select*fromtbl_namewherekey_column=10;select*fromtbl_nam ewherekey_columnbetween10and20;select*fromtbl_namewherekey_ columnin(10,20,30);select*fromtbl_namewherekey_part1=10andk ey_part2in(10,20,30);（10）index该联接类型与all相同,除了扫描索引树.其他情况都比all快,因为索引文件通常比数据文件小.当查询只使用作为单索引一部分的列时,mysql可以使用该联接类型.（11）all对于每个来自于先前的表的行组合,进行完整的表扫描.如果第一个表没标记为const,这样执行计划就不会很好.通常可以增加更多的索引来摆脱all,使得行能基于前面的表中的常数值或列值被检索出.possible_keyspossible_keys列指出mysql能供给使用的索引键有哪些.注意,该列完全独立于explain输出所示的表的次序.这意味着在possible_keys中的某些索引键实际上不能按生成的表次序使用.如果该列是null,则没有相关的索引.在这种情况下,可以通过检查where子句查看是否可以引用某些列或适合的索引列来提高查询性能.如果是这样,创造一个适当的索引并且再次用explain检查查询.如果要查询一张表有什么索引,可以使用showindexfromtbl_namekeykey列显示mysql实际决定使用的键（索引）.如果没有选择索引,那么可能列的值是null.要想强制mysql使用或忽略possible_keys列中的索引,在查询中可以使用forceindex--强逼使用某个索引useindex--使用某个索引ignoreindex--忽略某个索引对于myisam引擎和bdb引擎的表,运行analyzetable可以帮助优化器选择更好的索引.对于myisam表,可以使用myisamchk--analyze.key_lenkey_len列显示mysql决定使用的索引键的长度（按字节计算）.如果键是null,则长度为null.注意通过key_len值我们可以确定mysql将实际使用一个多索引键索引的几个字段.refref列显示使用哪个列或常数与索引一起查询记录.rowsrows列显示mysql预估执行查询时必须要检索的行数.extra该列包含mysql处理查询时的详细信息.下面解释了该列可以显示的不同的文本字符串:distinctmysql发现第1个匹配行后,停止为当前的行组合搜索更多的行.notexistsmysql能够对查询进行leftjoin优化,发现1个匹配leftjoin标准的行后,不再为前面的的行组合在该表内检查更多的行.下面是一个可以这样优化的查询类型的例子:select*fromt1leftjoint2ont1.id=t2.idwheret2.idisnull;假定t2.id定义为notnull.在这种情况下,mysql使用t1.id的值扫描t1并查找t2中的行.如果mysql在t2中发现一个匹配的行,它知道t2.id绝不会为null,并且不再扫描t2内有相同的id值的行.换句话说,对于t1的每个行,mysql只需要在t2中查找一次,无论t2内实际有多少匹配的行.rangecheckedforeachrecord(indexmap:#)mysql没有发现好的可以使用的索引,但发现如果来自前面的表的列值已知,可能部分索引可以使用.对前面的表的每个行组合,mysql检查是否可以使用range或index_merge访问方法来获取行.这并不很快,但比执行没有索引的联接要快得多.可以参考一下这篇文章:里面就提到了rangecheckedforeachrecordusingfilesortmysql需要额外的一次传递,以找出如何按排序顺序检索行.通过根据联接类型浏览所有行并为所有匹配where子句的行保存排序关键字和行的指针来完成排序.然后关键字被排序,并按排序顺序检索行如果是orderby操作就会用到这个usingfilesort,当然filesort不是指使用文件来排序,大家不要误会了...usingindex从只使用索引树中的信息而不需要进一步搜索读取实际的行来检索表中的列信息.当查询只使用作为单一索引一部分的列时,可以使用该策略.usingtemporary为了解决查询,mysql需要创建一个临时表来容纳结果.典型情况如查询包含可以按不同情况列出列的groupby和orderby子句时.一般用到临时表都会看到usingtemporaryusingwherewhere子句用于限制哪一个行匹配下一个表或发送到客户端.除非你专门从表中索取或检查所有行,如果extra值不为usingwhere并且表联接类型为all或index,查询可能会有一些错误.usingindexforgroup-by类似于访问表的usingindex方式,usingindexforgroup-by表示mysql发现了一个索引,可以用来查询groupby或distinct查询的所有列,而不要额外搜索硬盘访问实际的表.并且,按最有效的方式使用索引,以便对于每个组,只读取少量索引条目.descibe语句的使用方法与explain语句是一样的,并且分享结果也是一样的descibe语句的语法如下describeselectselect_optionsdescibe可以缩写成desc（2）索引对查询速度的影响mysql中提高性能的一个最有效的方式就是对数据表设计合理的索引.索引提供了高效访问数据的方法,并且加快查询速度因此索引对查询速度有着至关重要的影响.如果查询没有索引,查询语句将扫描表中所有记录.在数据量大的情况下,这样查询的速度会很慢.如果使用索引进行查询,查询语句可以根据索引快速定位到待查询记录,从而减少查询的记录数,达到提高查询速度的目的.下面是查询语句中不使用索引和使用索引的对比,首先分析未使用索引的查询情况,explain语句执行如下explainselect`id`,`name`from`test`.`emp`where`name`="nih ao"可以看到,rows列的值是3说“select`id`,`name`from`test`.`emp`where`name`="nihao"”语句扫描了表中的3条记录然后在emp表加上索引createindexix_emp_nameonemp(name)现在再分析上面的查询语句,执行的explain语句结果如下结果显示,rows列的值为1.这表示这个查询语句只扫描了表中的一条记录,其他查询速度自然比扫描3条记录快.而且possible_keys和key的值都是ix_emp_name,这说明查询时使用了ix_emp_name索引如果表中记录有100条、1000条、10000条优势就显现出来了（3）使用索引查询索引可以提高查询速度,但并不是使用带有索引的字段查询时,索引都会起作用.下面的几种情况跟跟sqlserver一样,有可能用不到索引（1）使用like关键字的查询语句使用like关键字进行查询的时候,如果匹配字符串的第一个字符为“%”,索引不起作用.只有“%”不在第一个位置,索引才会起作用使用like关键字,并且匹配字符串中含有“%”字符,explain语句如下usetest;explainselect*from`test`.`emp`where`name`like"%x ";usetest;explainselect*from`test`.`emp`where`name`like"x% ";name上有索引ix_emp_name第一个查询type为all,表示要全表扫描第二个查询type为index,表示会扫描索引like关键字是否能利用上索引跟sqlserver是一样的我之前写过一篇文章:（2）使用多列索引的查询语句mysql可以为多个字段创建索引.一个索引可以包括16个字段（跟sqlserver一样）对于多列索引,只有查询条件中使用了这些字段中的第一个字段时,索引才会被使用,这个字段叫:在表person中name,age字段创建多列索引,验证多列索引的情况createindexix_person_name_ageon`person`(name,age)explain selectid,name,age,jobfrom`person`where`name`="suse"explainselectid,name,age,jobfrom`person`where`age`=12从第一条查询看出,where`name`="suse"的记录有一条,扫描了一条记录并且使用了ix_person_name_age索引从第二条记录可以看出,rows列的值为4,说明共扫描了4条记录,并且key列值为null,说明explainselectid,name,age,jobfrom`person`where`age`=12语句并没有使用索引.因为age字段是多列索引的第二个字段,只有查询条件中使用了name字段才会使用ix_person_name_age索引这个跟sqlserver是一样的,详细请看:（3）使用or关键字的查询语句查询语句的查询条件中只有or关键字,而且or前后的两个条件中的列都是索引时,查询中才使用索引,否则,查询不使用索引查询语句使用or关键字的情况我们再创建一个索引createindexix_person_ageon`person`(age)explainselectname,agefrom`person`where`name`="suse"or`jo b`="sportman"explainselectname,agefrom`person`where`age`=2or`name`="s use"大家要注意,这里跟刚才不一样,这次我们select的字段只有name和age,而不是select出全部字段因为并没有在job这个字段上建立索引,所以第一个查询使用的是全表扫描第二个查询因为name字段和age字段都有索引,那么mysql可以利用这两个索引的其中之一,这里是ix_person_name_age索引来查找记录利用索引来查找记录会快很多（4）优化子查询mysql从4.1版本开始支持子查询,使用子查询可以进行select 语句的嵌套查询,即一个select查询的结果作为另一个select语句的条件子查询可以一次性完成很多逻辑需要多个步骤才能完成的sql操作.子查询虽然使查询语句灵活,但是执行效率不高.执行子查询时,mysql需要为内层查询语句结果建立一个临时表.然后外层查询语句从临时表中查询记录查询完毕后,再撤销临时表.因此,子查询的速度会受到一定影响,如果查询的数据量特别大,这种影响就会更大.在mysql中,可以使用连接（join）查询来代替子查询.连接查询不需要建立临时表,其速度比子查询快,如果查询中使用索引的话,性能会更好.所以很多网上的文章都说尽量使用join来代替子查询,虽然网上也说mysql5.7对于子查询有很大的改进,但是如果不是使用mysql5.7还是需要注意的如果系统中join语句特别多还需要注意修改my.ini或f 文件中的join_buffer_size大小,预防性能问题优化数据库结构一个好的数据库设计方案对于数据库的性能常常起到事半功倍的效果.数据库结构的设计需要考虑数据冗余、查询和更新速度、字段的数据类型是否合理等多方面（1）将字段很多的表拆分成多个表有时候有些字段使用频率很低或者字段的数据类型比较大,那么可以考虑垂直拆分的方法,把不常用的字段和大字段拆分出去（2）增加中间表对于需要经常联合查询的表,可以建立中间表以提高查询效率.通过建立中间表,把需要经常联合查询的数据插入到中间表中,然后将原来的联合查询改为对中间表的查询,以此来提高查询效率.（3）增加冗余字段设计数据库表时应尽量遵循范式理论,尽可能减少冗余字段,但是现今存储硬件越来越便宜,有时候查询数据的时候需要join多个表这样在高峰期间会影响查询的效率,我们需要反范式而为之,增加一些必要的冗余字段,以空间换时间需要这样做会增加开发的工作量和维护量,但是如果能换来可观的性能提升,这样做也是值得的（4）优化插入记录的速度插入记录时,影响插入速度的主要是索引、唯一性校验、一次插入记录条数等.根据实际情况,可以分别进行优化对于myisam表,常见优化方法如下:1、禁用索引对于非空表,插入记录时,mysql会根据表的索引对插入的记录建立索引.如果插入大量数据,建立索引会降低插入记录的速度.为了解决这个问题,可以在插入记录之前禁用索引,数据插入完毕后再开启索引禁用索引语句如下:altertabletable_namedisablekeys;其中table_name是禁用索引的表的表名重新开启索引语句如下:altertabletable_nameenablekeys;对于空表批量导入数据,则不需要进行此操作,因为myisam表是在导入数据之后才建立索引！2、禁用唯一性检查插入数据时,mysql会对插入的记录进行唯一性校验.这种唯一性校验也会降低插入记录的速度.为了降低这种情况对查询速度的影响,可以在插入记录之前禁用唯一性检查,等到记录插入完毕之后再开启禁用唯一性检查的语句如下:setunique_checks=0;开启唯一性检查的语句如下:setunique_checks=1;3、使用批量插入插入多条记录时,可以使用一条insert语句插入一条记录,也可以使用一条insert语句插入多条记录.第一种情况insertintoemp(id,name)values(1,"suse");insertintoemp(id, name)values(2,"lily");insertintoemp(id,name)values(3,"tom");第二种情况insertintoemp(id,name)values(1,"suse"),(2,"lily"),(3,"to m")第二种情况要比第一种情况要快4、使用loaddatainfile批量导入当需要批量导入数据时,如果能用loaddatainfile语句,就尽量使用.因为loaddatainfile语句导入数据的速度比insert语句快很多对于innodb引擎的表,常见的优化方法如下:1、禁用唯一性检查插入数据时,mysql会对插入的记录进行唯一性校验.这种唯一性校验也会降低插入记录的速度.为了降低这种情况对查询速度的影响,可以在插入记录之前禁用唯一性检查,等到记录插入完毕之后再开启禁用唯一性检查的语句如下:setunique_checks=0;开启唯一性检查的语句如下:setunique_checks=1;2、禁用外键约束插入数据之前执行禁止对外键的检查,数据插入完成之后再恢复对外键的检查.禁用外键检查的语句如下:setforeign_key_checks=0;恢复对外键的检查语句如下setforeign_key_checks=1;3、禁止自动提交插入数据之前禁止事务的自动提交,数据导入完成之后,执行恢复自动提交操作或显式指定事务（5）分析表、检查表、优化表、修复表和checksum表mysql提供了分析表、检查表和优化表的语句分析表主要是分析关键字的分布；检查表主要是检查表是否存在错误；优化表主要是消除删除或者更新造成的空间浪费修复表主要对myisam表文件进行修复checksum表主要对表数据传输前和传输后进行比较1、分析表mysql中提供了analyzetable语句分析表,analyzetable语句的基本语法如下analyze[local|no_write_to_binlog]tabletbl_name[,tbl_name ]...local关键字是no_write_to_binlog关键字的别名,二者都是执行过程不写入二进制日志,tbl_name为分析的表的表名可以有一个或多个使用analyzetable分析表的过程中,数据库系统会自动对表加一个只读锁.在分享期间,只能读取表的记录,不能更新和插入记录analyzetable语句能分析innodb、bdb和myisam类型的表使用analyzetable来分析emp表,执行语句如下:analyzetableemp;上面结果显示说明table:表示分析的表名op:表示执行的操作,analyze表示进行分析操作msg_type:表示信息类型其值通常是状态（status）、信息（info）、注意（note）、警告（warning）和错误（error）之一msg_text:显示信息实际上分析表跟sqlserver里的更新统计信息是差不多的主要就是为了索引的基数更加准确,从而使查询优化器能够更加准确的预估行数emp表的记录行数是18分析表之后,cardinality基数更加准确了2、检查表mysql中使用checktable语句来检查表.checktable语句能够检查innodb和myisam类型的表是否存在错误.对于myisam类型的表,checktable语句还会更新关键字统计数据.而且,checktable也可以检查视图是否有错误,比如在视图定义中被引用的表已不存在.该语句基本语法如下:checktabletbl_name[,tbl_name]...[option]...option={quick |fast|medium|extended|changed}其中,tbl_name是表名；option参数有5个取值分别是quick、fast、medium、extended、changed各个选项的意思分别是quick:不扫描行,不检查错误的连接fast:只检查没有被正确关闭的表medium:扫描行,以验证被删除的连接是有效的,也可以计算各行的关键字校验和,并使用计算出的校验和验证这一点extended:对每行的所有关键字进行一个全面的关键字查找.这可以确保表是100%一致的,但是花的时间较长changed:只检查上次检查后被更改的表和没有被正确关闭的表option只对myisam表有效,对innodb表无效.checktable语句在执行过程中也会给表加上只读锁.3、优化表mysql中使用optimizetable语句来优化表.该语句对innodb和myisam表都有效.但是,optimizetable语句只能优化表中的varchar、blob、text类型的字段optimizetable语句的基本语法如下:optimize[local|no_write_to_binlog]tabletbl_name[,tbl_nam e]...local和no_write_to_binlog关键字的意义和分析表相同,都是指定不写入二进制日志tbl_name是表名通过optimizetable语句可以消除删除和更新造成的文件碎片.optimizetable语句在执行过程中也会给表加上只读锁.提示:一个表使用了text或者blob这样的数据类型,如果已经删除了表的一大部分,或者已经对含有可变长度行的表（含有varchar、blob或text列的表）进行了很多更新,则应使用optimizetable来重新利用未使用的空间,并整理数据文件的碎片.在多数设置中,根本不需要运行optimizetable.即使对可变长度的行进行了大量更新,也不需要经常运行,每周一次或每月一次即可,并且只需要对特定表进行optimizetableoptimizetable语句类似于sqlserver的重建索引和收缩数据文件的功能4、修复表mysql中使用repairtable来修复myisam表,只对myisam和archive类型的表有效.repair[local|no_write_to_binlog]tabletbl_name[,tbl_name] ...[option]...option={quick|extended|use_frm}选项的意思分别是:quick:最快的选项,只修复索引树.extended:最慢的选项,需要逐行重建索引.use_frm:只有当myi文件丢失时才使用这个选项,全面重建整个索引.与analyzetable一样,repairtable也可以使用local来取消写入binlog.5、checksum表数据在传输时,可能会发生变化,也有可能因为其它原因损坏,为了保证数据的一致,我们可以计算checksum（校验值）.使用myisam引擎的表会把checksum存储起来,称为livechecksum,当数据发生变化时,checksum会相应变化.语法如下:checksumtabletbl_name[,tbl_name]...[quick|extended]quick:表示返回存储的checksum值extended:表示重新计算checksum如果没有指定选项,则默认使用extended.checksum表主要用来对比在传输表数据之前和表数据之后,表的数据是否发生了变化,例如插入了数据或者删除了数据,或者有数据损坏checksum值都会改变.优化mysql服务器水电费优化mysql服务器主要从两个方面入手,一方面是对硬件进行优化；另一方面是对mysql服务器的参数进行优化1、优化服务器硬件服务器的硬件性能直接决定着mysql数据库的性能.硬件的性能瓶颈直接决定mysql数据库的运行速度和效率.优化服务器硬件的几种方法（1）配置较大的内存.足够大的内存,是提高mysql数据库性能之一.内存速度比磁盘i/o快得多,可以通过增加系统缓冲区容量,使数据库在内存停留时间更长,以减少磁盘i/o（2）配置高速磁盘系统,以减少读盘等待时间,提高响应速度（3）合理分布磁盘i/o,把磁盘i/o分散在多个设备上,以减少资源竞争,提高并行操作能力（4）配置多处理器,mysql是多线程的数据库,多处理器可同时执行多个线程2、优化mysql的参数通过优化mysql的参数可以提高资源利用率,从而达到提高mysql服务器的性能的目的.mysql服务器的配置参数都在f或者my.ini文件的[mysqld]组中.下面对几个对性能影响较大的参数进行介绍我们先看一下与网络连接的性能配置项及对性能的影响.●max_conecctions:整个mysql允许的最大连接数；这个参数主要影响的是整个mysql应用的并发处理能力,当系统中实际需要的连接量大于max_conecctions的情况下,由于mysql的设置限制,那么应用中必然会产生连接请求的等待,从而限制了相应的并发量.所以一般来说,只要mysql主机性能允许,都是将该参数设置的尽可能大一点.一般来说500到800左右是一个比较合适的参考值●max_user_connections:每个用户允许的最大连接数；上面的参数是限制了整个mysql的连接数,而max_user_connections则是针对于单个用户的连接限制.在一般情况下我们可能都较少使用这个限制,只有在一些专门提供mysql数据存储服务,或者是提供虚拟主机服务的应用中可能需要用到.除了限制的对象区别之外,其他方面和max_connections一样.这个参数的设置完全依赖于应用程序的连接用户数,对于普通的应用来说,完全没有做太多的限制,可以尽量放开一些.●net_buffer_length:网络包传输中,传输消息之前的netbuffer初始化大小；这个参数主要可能影响的是网络传输的效率,由于该参数所设置的只是消息缓冲区的初始化大小,所以造成的影响主要是当我们的每次消息都很大的时候mysql总是需要多次申请扩展该缓冲区大小.系统默认大小为16kb,一般来说可以满足大多数场景,当然如果我们的查询都是非常小,每次网络传输量都很少,而且系统内存又比较紧缺的情况下,也可以适当将该值降低到8kb.●max_allowed_packet:在网络传输中,一次传消息输量的最大值；这个参数与net_buffer_length相对应,只不过是netbuffer的最大值.当我们的消息传输量大于net_buffer_length的设置时,mysql会自动增大netbuffer的大小,直到缓冲区大小达到max_allowed_packet所设置的值.系统默认值为1mb,最大值是1gb,必须设定为1024的倍数,单位为字节.●back_log:在mysql的连接请求等待队列中允许存放的最大连接请求数.连接请求等待队列,实际上是指当某一时刻客户端的连接请求数量过大的时候,mysql主线。
我的MYSQL学习心得（六）函数
我的MYSQL学习心得（六）函数我的MYSQL学习心得（六）函数我的MYSQL学习心得（一）简单语法我的MYSQL学习心得（二）数据类型宽度我的MYSQL学习心得（三）查看字段长度我的MYSQL学习心得（四）数据类型我的MYSQL学习心得（五）运算符我的MYSQL学习心得（七）查询我的MYSQL学习心得（八）插入更新删除我的MYSQL学习心得（九）索引我的MYSQL学习心得（十）自定义存储过程和函数我的MYSQL学习心得（十一）视图我的MYSQL学习心得（十二）触发器我的MYSQL学习心得（十三）权限管理我的MYSQL学习心得（十四）备份和恢复我的MYSQL学习心得（十五）日志我的MYSQL学习心得（十六）优化我的MYSQL学习心得（十七）复制这一节主要介绍MYSQL里的函数，MYSQL里的函数很多，我这里主要介绍MYSQL里有而SQLSERVER没有的函数数学函数1、求余函数MOD(X,Y)MOD(X,Y)返回x被y除后的余数，MOD()对于带有小数部分的数值也起作用，他返回除法运算后的精确余数SELECT MOD(31,8)2、四舍五入函数TRUNCATE(X,Y)TRUNCATE(X,Y)返回被舍去至小数点后y位的数字x。
若y的值为0，则结果不带有小数点或不带有小数部分。
若y设为负数，则截去（归零）x小数点左边起第y位开始后面所有低位的值。
SELECT TRUNCATE(1.32,1)TRUNCATE(1.32,1)保留小数点后一位数字，返回值为1.3TIPS：ROUND(X,Y)函数在截取值的时候会四舍五入，而TRUNCATE(x，y)直接截取值，并不进行四舍五入3、求余函数HEX(X)和UNHEX（X）函数有以下的代码可以演示HEX和UNHEX的功能：SELECT HEX('this is a test str')查询的结果为：746869732069732061207465737420737472SELECT UNHEX('746869732069732061207465737420737472')查询的结果为：this is a test str字符串函数计算字符串字符数的函数1、CHAR_LENGTH(STR)返回值为字符串str所包含的字符个数。
让我有很多心得体会英文
让我有很多心得体会英文Title: My Life Lessons and Experiences: A Journey of Growth and Self-DiscoveryIntroduction:Throughout my life, I have encountered numerous experiences that have shaped me into the person I am today. From personal relationships to academic pursuits, each encounter has left its indelible mark on my understanding of the world. In this essay, I will delve into the valuable life lessons and experiences that have contributed to my personal growth and self-discovery. Each experience, triumph, and setback has taught me essential lessons, allowing me to embrace life's challenges and opportunities with a renewed sense of purpose.Body:1. Building meaningful relationships:One of the most impactful lessons I have learned is the importance of building authentic and meaningful connections with others. Through various friendships and partnerships, I have realized that relationships founded on trust, empathy, and respect cultivate personal growth and mutual support. It is through these connections that we learn about ourselves and others, broadening our perspectives and contributing to personal and emotional development.2. Embracing change and adaptability:Life is a constant series of changes, and the ability to embrace them and adapt is crucial. Whether it is starting a new job oradjusting to life in a different country, I have learned that flexibility and adaptability are key to seizing opportunities and overcoming adversity. Embracing change has allowed me to develop resilience, assertiveness, and versatility, making me more prepared and open to life's uncertainties.3. Pursuing education and intellectual growth:Education is an invaluable asset that expands our horizons and equips us with the necessary tools to navigate life successfully. My academic experiences have taught me the importance of continuous learning and intellectual growth. By immersing myself in diverse subjects and engaging in deep critical thinking, I have broadened my knowledge and acquired essential skills to tackle complex problems. These experiences have also taught me the value of perseverance and dedication in achieving personal and professional goals.4. Cultivating a positive mindset:Having a positive mindset is essential in overcoming obstacles and adapting to challenging situations. Through various hardships and setbacks, I have come to understand the power of a positive outlook. By embracing optimism and focusing on solutions rather than dwelling on problems, I have been able to find hidden opportunities and turn setbacks into stepping stones. This mindset has not only bolstered my resilience but also enabled me to inspire and uplift those around me.5. Embracing diversity and fostering inclusivity:Living in a diverse and interconnected world, embracing diversity and fostering inclusivity has become increasingly important.Interacting with people from different cultures, backgrounds, and perspectives has helped me appreciate the value of inclusivity and the richness it brings to our lives. Through cross-cultural collaborations, I have learned the importance of empathy, acceptance, and respect, developing a global mindset that allows me to thrive in diverse environments.Conclusion:In conclusion, my life experiences have shaped me into a resilient, compassionate, and open-minded individual. Each encounter, whether positive or negative, has provided valuable insights and life lessons that have contributed to my personal growth and self-discovery. These experiences have taught me the power of building meaningful relationships, embracing change, pursuing education, cultivating a positive mindset, and embracing diversity. Moving forward, I am excited to continue this journey of self-improvement and embrace new experiences, knowing that every new encounter holds the potential for growth and enlightenment.。
心得体会英文缩写范文
心得体会英文缩写范文My experience and realization, abbreviated as "ER", is an essential part of my personal growth and development. Throughout my life journey, I have encountered numerous challenges and experienced various accomplishments that have shaped my character and perspective. Reflecting on these experiences has allowed me to gain valuable insights, leading to continuous self-improvement and further understanding of the world around me. In this essay, I will share some of my most significant ER moments.One of the first ERs in my life occurred during my high school years. I was faced with the overwhelming pressure of academic performance and the burden of balancing multiple extracurricular activities. As a result, I often found myself feeling stressed and burnt out. However, with time, I realized that it was crucial to prioritize and manage my time effectively. This realization led me to develop better organizational and time management skills, ultimately enabling me to excel in various areas of my life.Another pivotal ER moment happened when I participated in a volunteer program in a developing country. Witnessing the poverty and hardship that many people faced, I gained a newfound appreciation for the privileges and opportunities I had been given. This experience taught me the importance of empathy and compassion, prompting me to actively seek ways to contribute to the betterment of society. It also helped me understand that even the smallest actions can have a significant impact on the lives of others.Furthermore, my ERs during my college years were centeredaround my personal relationships and self-discovery. I experienced both heartbreak and the joy of new connections. Through these experiences, I came to recognize the significance of communication, trust, and respect in building healthy and fulfilling relationships. I also learned the importance of self-love and acceptance, as without them, it is challenging to form meaningful connections with others.In addition to personal experiences, I have also gained valuable ERs from various cultural and educational exposures. Traveling to different countries and immersing myself in diverse cultures has broadened my worldview and enhanced my understanding of global issues. By interacting with individuals from different backgrounds, I have developed a deeper appreciation for cultural diversity and the value it brings to society. These experiences have also challenged my preconceived notions and stereotypes, teaching me the importance of open-mindedness and embracing differences.Overall, my ERs have taught me several important lessons. Firstly, self-reflection and introspection are vital for personal growth and improvement. By taking the time to analyze my experiences and emotions, I can gain a better understanding of myself and make wiser decisions in the future. Additionally, embracing change and challenging myself is crucial for personal development. Stepping out of my comfort zone has allowed me to discover new passions, develop new skills, and broaden my horizons.Lastly, ERs have taught me resilience and the importance of a positive mindset. Life is filled with ups and downs, and it is essential to approach challenges with a strong belief in my abilitiesand a determination to overcome them. By viewing hardships as opportunities for growth, I have been able to transform difficulties into valuable learning experiences.In conclusion, my ERs have played a significant role in shaping my character and perspective. Through high school pressure, volunteer experiences, personal relationships, cultural exposures, and more, I have gained valuable insights and lessons that have contributed to my personal growth. These ERs have taught me the importance of self-reflection, embracing change, resilience, and maintaining a positive mindset. By continuously learning and evolving from my ERs, I am confident in my ability to navigate through life's challenges and achieve personal success.。
英语社会实践心得体会
英语社会实践心得体会One of the most important things I learned during my time at the shelter is the importance of empathy and understanding. It can be easy to dismiss the issues facing homeless individuals and simply label them as lazy or unmotivated. However, after spending time at the shelter, I now understand that the reality is much more complex. Many of the individuals I met had faced significant hardships in their lives, including traumatic experiences, mental health issues, and addiction. This experience has taught me the importance of looking beyond the surface and recognizing the humanity in all individuals, regardless of their circumstances.Additionally, my time at the shelter has highlighted the need for greater resources and support for homeless individuals. I was struck by the lack of affordable housing and meaningful employment opportunities available to the residents. It is clear that more needs to be done to address the root causes of homelessness and provide individuals with the support they need to rebuild their lives. This experience has motivated me to become more involved in advocacy and support efforts for homeless individuals in my community. Furthermore, my time at the shelter has reinforced the importance of community and connection. Many of the residents I met emphasized the impact of feeling isolated and disconnected from the larger community. As a volunteer, I was able to provide support and companionship to the residents, and I witnessed the positive impact that these interactions had on their well-being. This experience has shown me the power of small acts of kindness and the importance of building connections with those in need.Overall, my social practice experience at the homeless shelter has been incredibly meaningful and impactful. I have gained a greater understanding of the challenges facing homeless individuals, and I am more motivated than ever to work towards creating positive change in my community. This experience has taught me the importance of empathy, advocacy, and human connection, and I am grateful for the opportunity to have been a part of it. I am committed to continuing to support and advocate for homeless individuals and to work towards building a more compassionate and inclusive community for all.。
五一劳动心得英语作文
五一劳动心得英语作文The May Day holiday is always a time for rest and reflection. I spent the break with family and friends, enjoying the simple pleasures of life.First, I took a break from the daily grind and relaxedat home. It felt so good to kick back on the couch andwatch movies without any distractions. I even found time to cook a few meals, which was a treat since I usually rely on takeout.On another day, I decided to get some fresh air andwent for a hike with my buddies. The outdoors was a refreshing change from the city's hustle and bustle. We talked, laughed, and soaked in the beauty of nature. It reminded me of how important it is to spend time withpeople who make you feel good.Then, I visited my grandparents. They always have so many stories to share, and listening to them never gets old.We played some cards, had a delicious home-cooked meal, and just caught up on life. It was a reminder of the importance of family and maintaining those connections.Lastly, I used the holiday to catch up on some personal hobbies. I picked up a book I'd been wanting to read for a while and got lost in its pages. I also tried my hand at painting, which was a total mess but surprisingly relaxing. It was a nice reminder that it's okay to take time for yourself and do something just for fun.In conclusion, the May Day holiday was all about slowing down, reconnecting.。
我刚写完心得英语作文
我刚写完心得英语作文下载温馨提示:该文档是我店铺精心编制而成，希望大家下载以后，能够帮助大家解决实际的问题。
文档下载后可定制随意修改，请根据实际需要进行相应的调整和使用，谢谢!并且，本店铺为大家提供各种各样类型的实用资料，如教育随笔、日记赏析、句子摘抄、古诗大全、经典美文、话题作文、工作总结、词语解析、文案摘录、其他资料等等，如想了解不同资料格式和写法，敬请关注!Download tips: This document is carefully compiled by theeditor. I hope that after you download them,they can help yousolve practical problems. The document can be customized andmodified after downloading,please adjust and use it according toactual needs, thank you!In addition, our shop provides you with various types ofpractical materials,such as educational essays, diaryappreciation,sentence excerpts,ancient poems,classic articles,topic composition,work summary,word parsing,copyexcerpts,other materials and so on,want to know different data formats andwriting methods,please pay attention!I just finished writing my reflection in English. Here is my piece:Today was a rollercoaster of emotions. I woke up feeling tired and unmotivated, but as the day went on, my energy levels started to rise. It was like a switch had been flipped, and suddenly, I was ready to take on the world. I tackled my tasks with gusto and accomplished more than I had expected. It's amazing how a simple change in mindset can make such a difference.In the midst of my productivity, I encountered a setback. I made a mistake that cost me a lot of time and effort. Frustration washed over me like a tidal wave, threatening to drown my determination. But instead of wallowing in self-pity, I took a deep breath and reminded myself that mistakes happen. I refused to let it define my day. With renewed determination, I picked myself up and continued on my journey.As the day drew to a close, I reflected on all that I had achieved. Despite the ups and downs, I was proud of myself for pushing through. It's easy to get caught up in the negatives and overlook the positives, but today, I chose to focus on the wins. Each small victory added up to a greater sense of accomplishment. It's important to celebrate the small moments of success along the way.Looking back, I realized that my attitude played a significant role in shaping my day. When I approached challenges with a positive mindset, I was able to overcome them more easily. It's a reminder that our thoughts have power and can influence our experiences. I want to carry this lesson with me moving forward and continue to cultivate a positive outlook.In conclusion, today was a whirlwind of emotions and experiences. From feeling tired and unmotivated to finding a burst of energy, from encountering setbacks to celebrating victories, it was a day full of ups and downs. Through it all, I learned the importance of mindset andattitude. With the right mindset, we can conquer any obstacle that comes our way.。
2023年h实训心得体会(通用15篇)
2023年h实训心得体会(通用15篇)（经典版）编制人：__________________审核人：__________________审批人：__________________编制单位：__________________编制时间：____年____月____日序言下载提示：该文档是本店铺精心编制而成的，希望大家下载后，能够帮助大家解决实际问题。
文档下载后可定制修改，请根据实际需要进行调整和使用，谢谢!并且，本店铺为大家提供各种类型的经典范文，如合同协议、工作计划、活动方案、规章制度、心得体会、演讲致辞、观后感、读后感、作文大全、其他范文等等，想了解不同范文格式和写法，敬请关注!Download tips: This document is carefully compiled by this editor. I hope that after you download it, it can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you!Moreover, our store provides various types of classic sample essays, such as contract agreements, work plans, activity plans, rules and regulations, personal experiences, speeches, reflections, reading reviews, essay summaries, and other sample essays. If you want to learn about different formats and writing methods of sample essays, please stay tuned!2023年h实训心得体会(通用15篇)我们在一些事情上受到启发后，应该马上记录下来，写一篇心得体会，这样我们可以养成良好的总结方法。
ehs实习心得
2014-2-27 ----------------------本文档下载后可以编辑修改，在网上可以免费浏览，谢谢大家的支持～～～----------------------
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总之，“安全第一、坚持预防为主、”我们公司的安全工作任重而
道远，我坚信通过这一段时间的学习，让我受益匪浅、我将会不断的
丰富自己的专业知识掌握现场设备的基本情况ห้องสมุดไป่ตู้熟悉现场设备的安全
操作规程和其他业务工作，在上级领导和同事的指导和帮助下努力做
一个有思想、有内涵的专职安全管理员，为实现公司全体员工的健康
安全工作、为公司的发展壮大尽自己的绵薄之力。
ehs实习心得
----------------------本文档下载后可以编辑修改，在网上可以免费浏览，谢谢大家的支持～～～---------------------- ==============================================================================
----------------------本文档下载后可以编辑修改，在网上可以免费浏览，谢谢大家的支持～～～----------------------
【推荐下载】zhuy心得体会-word范文模板 (8页)
本文部分内容来自网络整理，本司不为其真实性负责，如有异议或侵权请及时联系，本司将立即删除！== 本文为word格式，下载后可方便编辑和修改！ ==zhuy心得体会篇一：学习教学设计心得体会学习教学设计心得体会王舟课堂教学是实施新课程的重要途径之一，而教师的课堂教学设计是教师实施课堂教学的一个先决条件。
教学设计的好坏，直接决定着课堂的质量、课程的落实。
如何进行教学设计？如何把握教学设计的重点？如何设计一个有效的教学过程？这都是我们要面对和解决的问题。
通过这次教学设计的探讨，我获益匪浅，在此谈谈我的一些学习心得。
我认为教学设计的重点，不管是确定教学的目标，还是教学的重点和难点，其实它都是要教师明确本堂课，我们要教会学生什么，以及解决学生什么问题。
因此我认为在进行教学设计时，应把握下面三个问题一、立足学生《数学课程标准》中指出：“由于学生所处的文化环境、家庭背景和自身思维方式的不同，学生的数学学习活动应当是一个生动活泼的、主动的和富有个性的过程。
”因此每一个学生的学习接受能力不同，特别是城乡学生的差别就更大，教师在教师设计时，就要考虑针对学生的实际水平进行教学设计，而不单单是考虑课程设计的安排和进度。
比如在引人各种方程的教学时，我们可能都会创设情境让学生列出各种方程，然后引入方程概念，但是如果在创设情境时设计的问题过高，就会影响本节课学生学习的积极性，偏移难点，而且会影响教学进度。
二、挖掘教材数学的许多概念、定理、思想的教学，都是采用螺旋式上升的。
因此教师在教学设计时，要把握一个总体的思路，在教学过程中要进行渗透。
比如在七下“4.1二元一次方程”中例题教学，例：已知方程3x+2y=10。
（1）用关于x的代数式表示y；（2）求当x=2,0,3时，对应的y的值，对本例题（1）中的变形是已经学习过的整式变形，对于变形的结果就是学生今后要学习的一次函数解析式。
而二元一次方程解的不唯一性，刚好体现了一次函数由无数个对应点组成的关系，这也是两者之间的一个联系，也是这两者教学的一个难点。
劳动心得英语作文五年级
劳动心得英语作文五年级Title: My Reflections on LaborAs a fifth-grade student, I have recently had the opportunity to participate in a variety of labor activities both at school and at home. Through these experiences, I have gained valuable insights and learned important lessons that I believe will benefit me throughout my life.Firstly, labor has taught me the significance of hard work and perseverance. Whether it was weeding the school garden or helping my parents with household chores, I realized that no task is too small or menial. Each job requires effort and dedication, and by putting in my best, I can achieve satisfying results. This understanding has motivated me to work harder in my studies as well.Secondly, I have learned the importance of teamwork. During our class clean-up sessions, we divided the tasks among us and worked together to complete them efficiently. I observed that when everyone contributes and collaborates, the workload becomes lighter, and we can accomplish more in less time. This has reinforced the value of cooperation and mutual support.Moreover, engaging in labor has helped me appreciate the efforts of others. I now understand the hard work that goes into making our school clean and organized, or preparing a meal at home. This has instilled a sense of gratitude in me, and I make an effort to express my appreciationto those who work tirelessly to provide for us.Another important lesson I have learned is time management. Labor requires planning and organizing one's time effectively to complete tasks on schedule. By managing my time efficiently, I have discovered that I can balance my responsibilities and still have time for relaxation and leisure activities.Lastly, labor has boosted my self-confidence. As I master new skills and complete tasks successfully, I feel a sense of accomplishment and pride. This has encouraged me to take on more challenges and push myself to my full potential.In conclusion, my experiences with labor have been invaluable. They have taught me the essence of hard work, teamwork, appreciation, time management, and self-confidence. These lessons will undoubtedly guide me as I continue to grow and face new challenges in life. I am grateful for the opportunities to learn through labor and will continue to embrace them with enthusiasm.。
心得体会 英文
心得体会英文During my journey of self-discovery and personal growth, I have learned numerous valuable lessons and gained a plethora of experiences that have shaped me into the individual I am today. Through this process, I have come to realize that self-reflection, perseverance, and adaptability are key elements in achieving personal success and fulfillment.Self-reflection has been an essential practice in my personal development. It involves examining my thoughts, emotions, and actions, allowing me to gain deeper insights into my strengths and weaknesses. By taking the time to reflect on my experiences, I have been able to identify areas I want to improve and set goals to accomplish. Self-reflection has also helped me understand the motives behind my actions and make conscious decisions aligned with my values. This process has allowed me to cultivate self-awareness and become more confident in myself and my abilities. Perseverance has played a significant role in overcoming challenges and achieving my goals. Life is full of obstacles and setbacks, but it is through perseverance that we can push through the toughest times. I have encountered failures and disappointments along my journey. However, instead of being discouraged, I have seen these setbacks as opportunities to learn and grow. I have learned that success is not measured by the absence of failures, but by the ability to rise above them. Through perseverance, I have discovered my own resilience and learned to never give up on my dreams, no matter how daunting they may seem.Adaptability has proven to be crucial in navigating the ever-changing world we live in. The ability to adapt to new environments and circumstances is essential for personal growth and success. Throughout my life, I have encountered numerous situations that required me to adapt quickly. Whether it was moving to a new city or starting a new job, adaptability has allowed me to embrace change and thrive in unfamiliar situations. By being open to new experiences and perspectives, I have expanded my horizons and developed a broader understanding of the world around me. This flexibility has enabled me to seize opportunities and discover new passions and interests along the way.Through self-reflection, perseverance, and adaptability, I have not only learned valuable life lessons but also grown as an individual. I have discovered my true passions and developed a clearer sense of purpose. By understanding my strengths and weaknesses, I have been able to focus on personal growth and continuous improvement. The challenges I have faced have taught me resilience and the importance of perseverance in the face of adversity. I have learned to embrace change and adapt to new environments, enabling me to navigate life's unpredictable journey. Moreover, the experiences I have gained have been invaluable in shaping my perspective and broadening my understanding of the world around me. Through travel and exposure to diverse cultures, I have learned to appreciate different viewpoints and embrace diversity. I have realized the importance of empathy and understanding, fostering meaningful connections and relationships with people from all walks of life.In conclusion, my journey of self-discovery and personal growth has been a transformative process. Through self-reflection, perseverance, and adaptability, I have learned invaluable lessons and gained experiences that have shaped me into the person I am today. It is through continuous introspection and self-improvement that I strive to become the best version of myself. I am grateful for the challenges and opportunities I have encountered along the way, as they have enabled me to grow, learn, and evolve.。
五一心得体会英语
五一心得体会英语My Reflections on the May Day HolidayThe May Day holiday is a highly anticipated break for people in China, as it provides an opportunity for them to relax, travel, and spend quality time with their loved ones. This year, I had the privilege of having a week-long holiday, and it was truly a refreshing and enlightening experience. During this time, I had the chance to reflect on various aspects of my life and gain new perspectives. In this essay, I would like to share my reflections and insights gained during the May Day holiday.First and foremost, the holiday allowed me to spend precious time with my family. In our fast-paced lives, it is often challenging to find quality time to connect with our loved ones. However, the May Day holiday gave me the perfect opportunity to strengthen my bond with my family. We engaged in various activities together, such as going on picnics, hiking, and simply relaxing at home. These activities not only brought us closer together but also reminded me of the importance of cherishing these moments with the people who mean the most to us.Moreover, the holiday provided me with a chance to reflect on my personal goals and aspirations. In the midst of our daily routines, it is easy to lose sight of our dreams and ambitions. However, during this break, I took the time to evaluate my current position and reevaluate my goals. I spent hours contemplating my strengths, weaknesses, and the steps needed to achieve my objectives. This reflection allowed me to gain a sense of clarity and motivation, providing me with a fresh perspective on my journey towardspersonal growth and success.Additionally, traveling during the May Day holiday was a significant aspect of my experiences. Exploring new places and cultures broadens one's horizons and brings about a deep sense of appreciation for diversity. During this holiday, I had the opportunity to visit several historical sites and immerse myself in different traditions. Each new place I visited offered unique insights and experiences, reminding me of the beauty and complexity of our world. Traveling not only allowed me to appreciate the wonders of nature but also gave me a newfound respect for the history and culture of different regions.Furthermore, the May Day holiday emphasized the importance of self-care and relaxation. In our daily lives, we often neglect self-care and end up experiencing burnout and fatigue. However, during this break, I made a conscious effort to prioritize self-care and engage in activities that brought me joy and relaxation. I indulged in my favorite hobbies, read books that had been gathering dust on my shelf, and simply spent time alone reflecting and rejuvenating myself. This focus on self-care taught me the importance of taking time for oneself and how it positively impacts our overall well-being.Lastly, the May Day holiday reinforced my appreciation for nature and the environment. During this break, I was able to spend a significant amount of time outdoors, surrounded by the beauty of nature. Whether it was hiking in the mountains or strolling along the beach, I felt a deep connection to the natural world. This experience made me realize the fragility of the environment andthe urgent need for its preservation. It ignited a desire within me to become more environmentally conscious and contribute towards creating a sustainable future.In conclusion, the May Day holiday provided me with a wealth of experiences and insights. It allowed me to strengthen my relationships, reflect on my goals, appreciate different cultures, prioritize self-care, and deepen my connection with nature. This break served as a reminder of the importance of taking time for oneself, finding balance in our lives, and cherishing the moments spent with our loved ones. May Day holiday has truly been a transformative and enriching experience, and I am grateful for the lessons it has imparted to me.。
2017年5月大学生实习心得体会范文
2017年5月大学生实习心得体会范文心得体会范文一直想做老师的我终于有机会在幼儿园实习，这得感谢园长的支持与信任，给了我们机会，让我们可以尽情地发挥自己的特长。
不知道是不是机会来的太巧还是我们的运气，竟然我可以在新开的托班开始实习，当然这也是考验我们耐心与锻炼我们能力的时候，因为我们带的班级可以算是全园最小的班级啊，但我们欣然接受了这项任务。
由于我们这个托班有大小年龄段的小朋友，最小18个月，最大有3岁，所以怕老师人手不够安排不过来，并安排了2位实习生，再有一个老老师带我们，再加一个生活老师。
这样我们这个班级就有4位老师组成，托班当然要经验丰富的老师带班啊，从中我们也可以学习不少经验。
我们这个班级目前有20个小朋友，他们每天来园基本在8点到8点半，然后开始吃点心，上课，户外活动，下午午睡醒来后就开始吃午餐，然后上艺术课，4点左右开始小朋友离园。
对我来说，现在已经基本熟悉了这里的环境。
教学，与幼儿园生活作息表。
现在班级中的小朋友都已经熟悉了我们，还叫我们老师好。
对我们来说真的很欣慰，虽然实习了没多久，但小朋友对我们都已经产生了依赖，这说明我们在小朋友的心中已经离不开了，这也可以看出我们小小的成绩。
我本来认为幼师是件很轻松的职业，只有踏入这个行业才知道并不然。
幼师首先对孩子要充满爱心，自己要有耐心，老师自己要有特长，要学会观察孩子的表现，发现他们的优点，培养他们的创新能力。
我们要学习的也很多，比如怎么布置每个月的主题，班级特色是什么?怎么为小孩创造良好的学习，娱乐，生活环境。
一系列的问题，都是我们要掌握的，考虑到我们现在小孩的年龄有的都不懂你们在讲什么更不用说上课了。
但是如果他们时间久了，慢慢习惯了，就要开始给他们上课，让他们要学习东西，我们也要像其他老师一样学会备课，备课是老师应该做的最基本的事情，我们也要不断学习老师的备课经验。
有了充分的准备，才能让小孩学到丰富的知识。
总的说来，我们既然已经走进了教师这个职业，那我们就一定要爱这份职业，最主要的一点要对孩子充满爱，这样孩子才会爱你，爱他们的老师，这也是我现在的一点小小体会，我觉得我要学习的东西无止境，要不断地积累经验!心得体会范文当今社会中，孩子的教育成为所有父母关注的问题。
美狐旅行社管理系统实践心得
美狐旅行社管理系统实践心得对于美狐管理系统我们是不陌生，大二的下半学期我们便接触了这个软件系统，属于专业实践课，对于我们旅游管理专业的学生是一个在机房对整个旅行团从发团到回团一个系统的了解和实践,我们从中学习了很多,并且对这个系统和实践有一个了解。
时隔一年我们有接触了这个软件就有一种不一样的感觉，毕竟我们大三了，接触社会的时间越来越近了，随意我们这次接触它可能更加的实用性，也没有像上次一样让专业老师很费口舌的进行讲解,只是对一些疑难问题的解释和相关问题的扩展和延伸，下面就让我来讲下对这个系统的第二次理解。
这个系统的第一步是发团，也是整个路线的基本工作，是在路线设计之中，对于我们要到达的地区的一些著名景点进行游览，当然有三天团五天团,这里面要注意的无非就是一些导游费，机场建设费，等等的，因为有些费用是个人的，有些费用是一个团的，所以要算的相对仔细，并且对于这个团队中可能有过生日的或者特殊情况的人的预算放到里面，到了这里我们基本上可以进行简单报价,对于这个团的成本做一个简单统计,并且根据这个简单的报价单进行收款，当然不能收的太过离谱，因为会有一些利润率的问题，到了这里我们就可以打出一张单据,报价单，也是我们很重要的基础单据，到这里我们在线路设计里面的一些基本问题和一些相关问题都解决了。
第二步我们来到了外联销售首先要先找到我们刚才的那张订单，因为我们要看相关的游客信息,生成游客的订单，当然在游客订单里我们要写一些时间，地点，保险等等，然后保存，然后到订单管在订单管理中找到线路新增收款通知单，填表并看是收全款还是按百分比收还第三步我们要到财务，按时间找到自己的线路，在收退款通知单确认收款。
然后在计调操作在订单处理找出线路，根据该订单生成团队把仅显示当前在计调中生成的订单的勾挑掉才可找出线路，填写团队订单的时间、地点、标志、说明由于不可抗力导致旅行线路的取消或更改旅行社概不负责、团号；在组团团队中按出团时间找到线路；设置结算金额、结算单位、导游、补助、备用金、付款方式要点是全选和预算金额=预付金额，结算单位为旅行社是签证、综合、导服。
h5实训心得体会范文
h5实训心得体会范文当我们经过反思，对生活有了新的看法时，将其记录在心得体会里，让自己铭记于心，这样可以不断更新自己的想法。
那么你知道心得体会如何写吗？下面是小编精心整理的h5实训心得体会范文，供大家参考借鉴，希望可以帮助到有需要的朋友。
回顾这一个月来的实习生活是一件很值得纪念的事，这是我第一次在外实习，第一次在网上投简历能收到回复。
对于我们这样的艺术设计学生，我深刻的体会到单单是学校教的远远不够，学校教的很笼统，很抽象，很大概，如果可以，我希望这个专业的师弟师妹们，有空多多到图书馆充实自己，静下心来充分自学。
在外实习前，第一件事是把自己卖出去，包装自己，所以简历很重要，务必属实，因为你有多少两重，阅人无数的人事主管和老板在面试的交谈中很快就能从你各方面行为和语言中找到答案。
既然要面试，衣服当然要穿正装，其实我也想的只是大二实习期没有大三的三个月那么长，就那么一个月。
这样短期的工作其实根本没有什么公司愿意招聘，所以我感觉到万分荣幸能够进到这一支专业的创业团队，真的是一件了不起的事，而且这个岗位与我学习的和自己喜爱的科目对的很准，我自己也十分乐于这份工作。
记得刚开始的一个多星期，公司并没有让我马上投入工作，因为当时对产品了解不熟悉，要从学校的圈子走出来到商业模式去还是有点顾虑，但是当你接触到这商业化的东西，你会发现，学校的东西远远不足。
所以一般公司会进行些培训，很感激william杨，他提供了很多设计的书籍给我自学阅读，可惜在我深刻读完《瞬间之美--web界面设计如果让用户心动》(点击跳到本人的读书笔记)一书后，就再也很难抽取一点时间来阅读了。
在接下来的这个月里，除了必要的培训以熟悉公司及其产品知识外，我也开始忙碌起来，因为产品的第一个内部版本需要再X月X日这个好日子发布。
刚开始的两个星期，因为对产品并不熟悉，一直以来在学校设计的作品都很“学校”但是商业设计比较少，出头设计的时候真的抓破头脑，因为习惯了学校的生活，习惯了客户给要求按照客户的想法去做。
英语实践心得体会(10篇)
英语实践心得体会(10篇)（经典版）编制人：__________________审核人：__________________审批人：__________________编制单位：__________________编制时间：____年____月____日序言下载提示：该文档是本店铺精心编制而成的，希望大家下载后，能够帮助大家解决实际问题。
文档下载后可定制修改，请根据实际需要进行调整和使用，谢谢!并且，本店铺为大家提供各种类型的经典范文，如工作总结、工作计划、报告大全、心得体会、条据书信、合同协议、演讲稿、自我鉴定、其他范文等等，想了解不同范文格式和写法，敬请关注!Download tips: This document is carefully compiled by this editor.I hope that after you download it, it can help you solve practical problems. The document can be customized and modified after downloading, please adjust and use it according to actual needs, thank you!In addition, this shop provides you with various types of classic sample essays, such as work summary, work plan, report book, experience and experience, letter of agreement, contract agreement, speech draft, self-assessment, other sample essays, etc. I would like to know the different format And how to write, stay tuned!英语实践心得体会(10篇)下面是本店铺本店铺分享的英语实践心得体会(10篇)（大学生英语实践心得体会），欢迎参阅。
maya学习心得（精选3篇）
maya学习心得（精选3篇）maya学习心得（精选3篇）maya学习心得一:maya 学习心得maya是美国那边的顶级动画软件,应用的是非常的广泛,无论是在动画片里,还是在影视特效里,都是可以运用的.maya功能完善,工作灵敏,易学易用,制造听从极高,衬着的确感极强,是影戏级此外高端产软件.电影《阿凡达》中许多人物殊效等于通过这款软件出产,而国表里良多电影、电视、广告的特效也都离不开这款软件.所以假设你想要成为一位专业的影视制造人,学好maya是必须的.由于maya的功能非常的强大,所以说在试用玛雅的时候非常的困难的,想要学好maya这个软件不是那么轻而易举的.但是maya只管浅易,但只有静心去学,学不会是不行能的,而且我敢肯定人人均可以学会maya,关头是一种深造法子,这也是我写这篇文章的初志,盼愿人人少走弯路!具体形式各人往下看就知道了,必然对你有所募捐.在接触maya之前一直觉得这个软件很神秘,当栩栩如生的三维动画就是用它制作出来的,我又对这个软件产生了几分“爱意”。
带着这份“爱意”我到清美报名了,接待的老师很热情,教学老师也很认真负责,这里不累赘阐述。
下面就我第一阶段的学习作一个简单的心得汇报: 许多初学者问学习maya有没有捷径,我觉得学习是没有捷径可言的,唯一的捷径就是不断的学习和练习,只有这样才能学到真功夫,废话不说了,我再次整理一些自己学习maya的心得体会,希望对大家有所帮助。
1)先概述一下maya吧.maya应该来说,是一个比较全面,功能强大的3d动画软件,他的特色就是灵活,你能够掌握动画的方方面面,控制每一步的流程,甚至通过mel接触maya的底层----dg.如果要挑缺点的话,有两个,1,很难上手,2,默认渲染器与其他软件相比,较差.但是和他的灵活性比起来,又微不足道.maya在美国,日本,加拿大,澳大利亚比较流行,我看过他们的一些图形杂志,maya都是大片广告,相反3dmax很少.在中国刚好相反,maya只找了一个代理:特新科技,意思一下.在学习之前,最好先给自己定位,maya是针对高端影视特效,动画.如果志向是静帧,效果图,建议学习3dmax,这里没有什么软件高低好坏之分,只是上手快慢,出成绩的问题.就以动画流程说说吧.2)先说一下各模块的大概吧.modeling----maya的建摸工具基本够用,nurbs,polygan,subdiv 是三种基本的面,各有优势,用polygan的人较多,应为工具全,摸型布线方便,但是有个问题,就是很容易,造成面数过多,拖慢电脑,nurbs刚好相反,几条线,就搞定一个面.谁都不能代替谁,老外一般的做法是先用nurbs作出大概形状,然后转成polygan,重新布线,最后再转subdiv做动画.如果是电影,会用nurbs做最终的摸.中国基本用polygan跑完全程,除了慢一点,还没发现有啥坏处.以建人为例,制作之前,你要注意几点:做出来的模型要象人,你肯定要清楚人体解剖,为什么有的人出来象一个吹气公仔,就是因为缺少真人的细节,比如骨点.这方面你可以买本艺用人体结构学看看,一定有收获.还有一点,注意布线,如果布线不合理,模型根本不能用来做动画,布线的走向主要根据肌肉的走向和动画动作的要求,布线的拓扑学是一个很深的话题,以免跑题就到此为止.建议多找外国的线框图研究一下规律,还有,在cdv上,有一个叫”我乱讲的”斑竹,是工业光魔的人,是建模高手中的高手.大家可以看一下他的教程.再多说一句,simplymaya的建模教程,不适用于表情动画,建议你不要照抄.(如果你不同意,就当我没说吧,呵呵)建模方面还有几点要留意的,布线要平均,不要太疏,也不要太密,尽量保持4边形面,线与线之间的交点,也尽量保持在+,不要出现5星面或以上.这些要从建模的开始就注意,对于以后的贴图,模型间的转换,扫权重,动画,变形等一系列的工作,都大有好处,不至于你的作品半途而废。