问题描述
Oracle 区分大小写而 SQL Server 和 MySQL 等其他软件默认不区分大小写是否有原因?
我知道有一些方法可以启用/禁用区分大小写，但 oracle 与其他数据库的不同似乎很奇怪.
I know that there are ways to enable/disable case sensitivity, but it just seems weird that oracle differs from other databases.
我也在尝试了解区分大小写的原因.我可以看到Table"和TaBlE"在哪些地方可以被视为等效而不是等效的，但是是否有区分大小写实际上会产生影响的示例?
I'm also trying to understand reasons for case sensitivity. I can see where "Table" and "TaBlE" can be considered equivalent and not equivalent, but is there an example where case sensitivity would actually make a difference?
我对数据库有点陌生，目前正在上课.
I'm somewhat new to databases and am currently taking a class.
推荐答案
默认情况下，Oracle 标识符(表名、列名等)不区分大小写不区分.您可以通过在它们周围使用引号使它们区分大小写(例如:SELECT * FROM "My_Table" WHERE "my_field" = 1).SQL 关键字(SELECT、WHERE、JOIN 等)始终不区分大小写.
By default, Oracle identifiers (table names, column names, etc.) are case-insensitive. You can make them case-sensitive by using quotes around them (eg: SELECT * FROM "My_Table" WHERE "my_field" = 1). SQL keywords (SELECT, WHERE, JOIN, etc.) are always case-insensitive.
另一方面，字符串比较区分大小写敏感(例如:WHERE field='STRING' 将仅匹配 'STRING') 默认情况下.您可以通过将 NLS_COMP 和 NLS_SORT 设置为适当的值来使它们不区分大小写(例如:LINGUISTIC 和 BINARY_CI，分别).
On the other hand, string comparisons are case-sensitive (eg: WHERE field='STRING' will only match columns where it's 'STRING') by default. You can make them case-insensitive by setting NLS_COMP and NLS_SORT to the appropriate values (eg: LINGUISTIC and BINARY_CI, respectively).
注意:在查询数据字典视图(例如:dba_tables)时，如果您创建的名称不带引号，则名称将为大写，并且将适用第二段中解释的字符串比较规则在这里.
默认情况下，某些数据库(Oracle、IBM DB2、PostgreSQL 等)将执行区分大小写的字符串比较，其他数据库不区分大小写(SQL Server、MySQL、SQLite).这无论如何都不是标准的，所以请注意您的数据库设置是什么.
Some databases (Oracle, IBM DB2, PostgreSQL, etc.) will perform case-sensitive string comparisons by default, others case-insensitive (SQL Server, MySQL, SQLite). This isn't standard by any means, so just be aware of what your db settings are.
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