六、oracle和informix表的限制 1、在informix的一个表中对以上字符串类型定义的总长度不能超过32767(不包括对大字段处理的text类型) 但是遇到varchar与nvarchar会再减1(为该列设置索引会留一位)，而遇到lvarchar则需要减3。 2、oracle限制的每个表的列的总数不能超过1000(此处没有测试),然后每个列的长度由其数据类型决定。 每个索引的最大列数 32

在informix中有如下几种对字符串操作的类型： char(character),varchar,nchar,nvarchar,lvarchar,text 在ORACLE中有如下几种对字符串操作的类型： char(character),varchar(varchar2),nchar,nvarchar2,long,long raw及LOB类型

一、基本概念： 1、字符存储单位 2、char:定长的字符串类型 3、varchar：描述变长字符串

二、INFORMIX ORACLES数据类型对应长度及比较 informix Oracle 范围 默认长度 作为数据存储 变量 char 1~32767 1 1~2000 1~32767 varchar 1~255 1 1~4000 1~

三、字符比较： 1、char和varchar 2、char和nchar，varchar和nvarchar

四、oracle里的数据类型: 1、char,character,varchar,varchar2,nchar,nvarchar2的共同特点： 当插入空字符串时，则都会被转变为null

五、informix里的字符: 1、lvarchar在9.4版本之后才可以用带指定长度的方式，如lvarchar(3000)，不带长度则默认是2048字节，最大长度是32,739字节。 所以对于9.4之前的版本，不能用带长度的表达式，数据库会报语法错误。

七、行迁移与行链接 当一行的数据过长而不能插入一个单个数据块中时，可能发生两种事情：行链接(row chaining)或行迁移(row migration)。

八、ORACLE－在设计数据库时如何选择正确的数据类型

I hope that my daughter grows up empowered and doesn't define herself by the way she looks but by qualities that make her a intelligent, strong and responsible woman.

If anything, 'Fifty Shades of Grey' is a generic romance cynically engineered to appeal to the lowest common denominator of female fantasy.

I am a celebrity, but I don't want people standing outside my wedding venue.

I don't go to work thinking, 'Right, I'm going to be more heart-throbby today.'

There are times when the world is rearranging itself, and at times like that, the right words can change the world.

Theatre is more exciting in the sense that you can actually see the audience in the eye. You know there are no takes and retakes. You have one chance to do your job... and you better do it well!

I went to boarding school at seven and cried and cried.

When something isn't done, you want to do something about it.

The weak in courage is strong in cunning.

I'm not a very good lover. I'm so nervous about my sexuality.

There is more to life than surviving.

If you feel sick and tired of how things are in your life, chances are it's because you're making yourself sick and tired - by engaging in too many energy leaking things.

The very act of preparing and serving tea encourages conversation. The little spaces in time created by teatime rituals call out to be filled with conversation. Even the tea itself - warm and comforting-inspires a feeling of relaxation and trust that fosters shared confidences.

I'm not sought after. I never get enough work. It's the history of my career. There just isn't anything to turn down, let me put it that way.

But I think Steve's main contribution besides just the pure leadership is his passion for excellence. He's a perfectionist. Good enough isn't good enough. And also his creative spirit. You know he really, really wants to do something great.

I've been used to being my own boss for a really long time, so I don't take to authority very well.

Barack Obama is one of the greatest politicians in American history.

I love dressing up. As kids, my friends and I would dress up as the Spice Girls - Posh Spice was my favourite because I had short brown hair like her.

I think extreme sports are really good for relieving stress.

Darling I'm a nightmare dressed like a daydream.

I'm not sure a world run by women would be any better. They're human beings!

Thank you to the children whose innocent words encouraged me.

Beauty shouldn't be about changing yourself to achieve an ideal or be more socially acceptable. Real beauty, the interesting, truly pleasing kind, is about honoring the beauty within you and without you. It's about knowing that someone else's definition of pretty has no hold over you.

I can see now that a concept or even a feeling makes no sense unless out of our substance we spin around it a web of references, of relationships, of values.