Hubbledotnet open-source full-text search database project-data type and index type of data tables

Source: Internet
Author: User
Data Type

Hubbledotnet currently supports the following data types:

Int, tinyint, smallint, bigint, float, datetime, smalldatetime, date, nvarchar, varchar, nchar, char

The range of datetime is the same as that of. Net datetime, and the precision is millisecond.

The range of smalldatetime ranges from January 1-20, 1980 to December 31 23:59:59, precise to seconds.

The range of date is from January 1, January 1-5, 0001 to January 1, January 1, 3516.

Nvarchar, varchar, nchar, and char correspond to the four types of SQL Server 2005. You can specify the length of a string or use Max to specify a string of unlimited length.

If the above type is used for untokenized index, the maximum length is 32.

Int, tinyint, smallint, bigint, float correspond to the corresponding types of SQL Server 2005. These types can only be specified as none or untokenized indexes, but cannot be specified as tokenized indexes.


The field name definition is similar to the T-SQL, if it is a keyword, it is specified with single quotes, such as 'where '.


Index type provides three index types

Tokenized Index

Tokenized indexes are full-text indexes. Only string fields can be specified as tokenized indexes. After a field is specified as this index type, the text in the field is first segmented, and an inverted index is created for the word splitting result. When you search for these fields, you will query the inverted index and find the corresponding records.


Untokenized Index

The untokenized index is a single-value index, which can be specified for all data types. After the field is specified as this index type, a single-value index will be created for the data in the field during the index and stored in the payload. DB file. This type of index is used only when the full text and metadata are searched at the same time. For example, if the full text is searched and the search time or the time is sorted, a single-value index is used.


None index type

If the index type of a field is set to none, will not create an index for this field. If the search condition contains a field of this index type, queries the index of the relational database itself. If the index needs to search for the none field, you need to consider creating an appropriate index in the table corresponding to the relational database.


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