You can use the search bar to search throug the document in a corpus. By de fault, you will be searching through all text fields, but you can also select specific fields to search through.
You can type in multiple query terms. For example, if you type in tram bike, you will search for documents that contain tram and/or bike.
It is also possible to formulate more advanced queries. We use the simple query string syntax of elasticsearch (our database system). This notation is explained in more details in the Simple Query String manual of Elasticsearch itself.
For your convenience, a summary of the search operators is shown below.
Simple Query String Syntax
The search method supports the following operators:
| Operator | Description |
|---|---|
+ |
means AND (bank AND assets) |
| | | means OR (bank OR assets). Note that OR is already the default way to combine search terms, so bank assets would be sufficient in this example. |
- |
means NOT (NOT assets) |
" |
allows the search for an entire phrase “the assets of the bank” |
* |
a wildcard for any number of characters, e.g. bank* will match banking, banks, banked, etc. The wildcard isnly allowed at the end of a word, and cannot be used with phrases (between " quotes). |
~N |
Describes fuzzy search. When placed after a term this signifies how many characters are allowed to differ. These can be insertions, deletions, substitutions or swapping of characters. So bank~1 also matches bang, sank, dank, bark, bakn etc. |
~N |
When placed after a phrase, this signifies how many words may differ. These can be insertions, deletions, substitutions or swapping of words. |
Symbols such as | and + are reserved characters. If you want to search for text containing these characters then they should be escaped by prefixing them with \. For example, bank + assets matches documents with both bank and assets, and bank \+ assets will search for either bank, the plus sign, or assets.
By default the search will combine all terms using OR. This means that when you type: Tram Bike, documents will be searched containing Tram and/or Bike. This also has implications for the –operator. Tram Bike –Car becomes documents containing Tram, Bike or any document not containing Car. A more expected result could be obtained by using (Tram Bike) +-Car which will return all hits containing Tram or Bike and withhold all those containing Car.
Be Careful with Spaces
Adding or removing a space can change the results of your query. For example search for +- term is different than searching for +-term. It might be necessary to escape a space (also by placing a \ in front of it).
Advanced options to search for combinations of words
The Elasticsearch query syntax also allows fuzzy matches on a word level. This can be used to construct queries in which two words should appear no more than n words apart. For instance,
"interest balance"~5
would find all documents in which the terms "interest" is followed by "balance", separated by no more than 5 words.
You can also query for both orders. The following query means: find all documents in which "interest" is followed by "balance", OR vice versa, separated by no more than 5 words:
"interest balance"~5 "balance interest"~5
Note that for stemmed text fields (see section "Stemming" below), this could also lead to hits containing phrases such as "interesting balance".
Examples of Search Results
Illustrating the differences when searching for different combinations of bank and assets.
| Query | Hits |
|---|---|
assets |
568 hits |
bank |
76161 hits |
bank +assets |
256 hits (bank AND assets) |
+bank +assets |
256 hits (AND bank AND assets) |
+bank +-assets |
75905 hits (bank AND not assets, or: documents containing bank but not assets) |
+-bank +assets |
312 hits (not bank but assets) |
"assets of the bank" |
2 hits |
assets deposit |
632 hits |
+assets +deposit |
27 hits |
asset* |
910 hits |
*asset |
There were no results to your query. |
bank~1 |
76241 hits (compare with just bank) |
"assets of the bank" |
3 hits |
"assets of the bank" ~2 |
10 hits |
"assets bank"~5 "bank assets"~5 |
350 hits |
Stemming
Some corpora support stemming in the main content field. This means that when you search for banking, you will also find documents that contain banks, bank, etc. (However, a document that contains banking will get a higher relevance score than one with banks.)
For corpora that support stemming, the list of search fields will include the stemmed text. For example, you can select both Content and Content (stemmed). If you do not want to search with stemming, you can select just the Content field.
