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content SHORTTEXT(100)
Changes to SHORTTEXT(n) Indexes
FAST PREPROCESS OFF
SEARCH ONLY ON
SHORTTEXT(n) full text indexes are automatically generated and you do not specify names for them; therefore,
you cannot directly manipulate them. However, when you create, alter, or drop a table column, the same change
is automatically applied to the index for that column.
When using the ALTER TABLE statement to affect changes on the index, you can only alter the following
parameters:
● PHRASE INDEX RATIO
● FUZZY SEARCH INDEX
Note: You cannot change the length of the original text and you cannot convert SHORTTEXT(n) to another
data type.
Manually Created Indexes
If the tables in your SAP HANA database contain extensive columns that are frequently queried but do not have
automatically generated full text indexes, meaning they are not TEXT or SHORTTEXT(n) type columns, you can
improve search performance by manually creating full text indexes.
To manually create a full text index, the column must have one of the following SQL data types:
● VARCHAR
● NVARCHAR
● ALPHANUM
● CLOB
● NCLOB
● BLOB
When you manually create an index, the system attaches a hidden column to the specified column. This hidden
column contains textual data that SAP HANA Preprocessor has extracted from the text in the source column. The
original text in the source column remains unchanged. Search queries are then performed on the hidden column;
however, they always return the original text. Depending on the data type that is assigned to a source column,
string search may be possible.
You can manually create an index directly after creating a table or you can create the index later. Once you create
an index for a column, the system automatically processes any text that is inserted into this column and adds the
processed text to the index. Processing for manually created indexes can be performed synchronously or
asynchronously.
You can specify different parameters when you create a full text index. If parameter changes are required later,
you can change the values for the existing index directly or re-create the index with the parameters that you want
to change.
Related Links
Creating Full Text Indexes [page 235]
SAP HANA Developer Guide
Enabling Search
P U B L I C
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