Choose any three.
|
|
SQLite里的SQL
SQL As Understood By SQLite
REINDEX
REINDEX命令用对混乱的索引进行删除重建。当排序器的定义发生变动时这个命令是非常有用的。
The REINDEX command is used to delete and recreate indices from scratch.
This is useful when the definition of a collation sequence has changed.
如果REINDEX关键词没有后面没有指定排序器或者数据库对象标识，那么所有附加库上的所有索引都会被重建。
If the REINDEX keyword is not followed by a collation-sequence or database
object identifier, then all indices in all attached databases are rebuilt.
如果REINDEX指定了一个排序器名，那么所有库上的所有使用了这个排序器的索引都会被重建。
If the REINDEX keyword is followed by a collation-sequence name, then
all indices in all attached databases that use the named collation sequences
are recreated.
或者，如果REINDEX指定了一个数据库表，那么所有附属于这个表的索引都会被重建。如果指定的是一个数据库索引，那么只有这个索引会被重建。
Or, if the argument attached to the REINDEX identifies a specific
database table, then all indices attached to the database table are rebuilt.
If it identifies a specific database index, then just that index is recreated.
如果没有指定database-name并且存在同名的排序器和表或索引，那么SQLite会认为这是要重建所有使用该名字排序器的索引。当需要更新指定的表或索引是，这个模糊的情况可以通过总是指定database-name来避免。
If no database-name is specified and there exists both a table or
index and a collation sequence of the specified name, SQLite interprets
this as a request to rebuild the indices that use the named collation sequence.
This ambiguity in the syntax may be avoided by always specifying a
database-name when reindexing a specific table or index.