not null的意思

not null中文翻譯：

非空

相似詞語短語

null island───空島

assert null───斷言為空

null definition───空定義

null bot───空機器人

null byte───空字節

igneous null───火成巖零

token null───標記為空

drools null───無人機零點

aleph null───aleph空

雙語使用場景

If not NULL, increment the line counter.───如果不是NULL，則增加行計數器。

NOT NULL - a NULL was found in field name.───NOT NULL——字段名中出現空值。

Restrictions and usage notes on DROP NOT NULL───DROP NOT NULL 的限制和使用說明

This routine initially checks if the passed inquiry context is not NULL and if it a context for group member.───它首先檢查傳遞的查詢上下文是否非NULL，以及是否是組成員的上下文。

Though you did not specify that column, the Rails migration created it for you anyway, with auto_increment and NOT NULL.───雖然沒有指定這個列，但是Rails遷移會自動創建它，并具有auto_increment和NOTNULL屬性。

The following table illustrates the relationship between the existence of a default and the definition of a column as NULL or NOT NULL.───下表說明默認值的存在與將列定義為NULL或NOTNULL之間的關系。

A computed column cannot be used as a DEFAULT or FOREIGN KEY constraint definition or with a NOT NULL constraint definition.───計算列不能用作DEFAULT或FOREIGNKEY約束定義，也不能與NOTNULL約束定義一起使用。

In MySQL, if you try to execute an INSERT statement that does not provide a value for a NOT NULL column, the command is successful.───在MySQL中，如果要執行一個不提供NOTNULL列值的INSERT語句，此命令沒有問題。

We recommend that you explicitly specify NULL or NOT NULL for each column in a temporary table.───建議對于臨時表中的每列，顯式指定NULL或NOTNULL。

英語使用場景

Unless you have a very specific reason to use a NULL value, you should always set your columns as NOT NULL.

If you assume that an argument is not NULL, for example, use an assertion statement to check for that assumption.

If the customer number is not null, that is, the customer is already known, the left hand path is followed (2), and the customer data is retrieved from the customer registration service (3).

This new validation will enforce NOT NULL column constraints by rejecting null values, but only in situations where your database would reject a null value.

If defined as NOT NULL, the value corresponds to the start time associated with the most recent transaction (the value of the AS ROW BEGIN column).