Wildcard Search with ArangoSearch

Search for strings with placeholders that stand for one or many arbitrary characters

You can use the LIKE() function for this search technique to find strings that start with, contain or end with a certain substring, but it can do more than that. You can place the special characters _ and % as wildcards for single or zero-or-more characters in the search string to match multiple partial strings.

The ArangoSearch LIKE() function is backed by View indexes. In contrast, the String LIKE() function cannot utilize any sort of index. Another difference is that the ArangoSearch variant does not accept a third argument to make matching case-insensitive. You can control this via Analyzers instead, also see Case-insensitive Search with ArangoSearch. Which of the two equally named functions is used is determined by the context. It is the ArangoSearch variant in SEARCH operations and the String variant everywhere else.

Wildcard Syntax

• _: A single arbitrary character
• %: Zero, one or many arbitrary characters
• \\_: A literal underscore
• \\%: A literal percent sign

Wildcard Search Examples

Dataset

IMDB movie dataset

View definition

search-alias View

db.imdb_vertices.ensureIndex({ name: "inv-exact", type: "inverted", fields: [ "title" ] });
db._createView("imdb", "search-alias", { indexes: [ { collection: "imdb_vertices", index: "inv-exact" } ] });

arangosearch View

{
  "links": {
    "imdb_vertices": {
      "fields": {
        "title": {
          "analyzers": [
            "identity"
          ]
        }
      }
    }
  }
}

AQL queries

Match all titles that starts with The Matr using LIKE(), where _ stands for a single wildcard character and % for an arbitrary amount:

FOR doc IN imdb
  SEARCH LIKE(doc.title, "The Matr%")
  RETURN doc.title

You can achieve the same with the STARTS_WITH() function:

FOR doc IN imdb
  SEARCH STARTS_WITH(doc.title, "The Matr")
  RETURN doc.title

Match all titles that contain Mat using LIKE():

FOR doc IN imdb
  SEARCH LIKE(doc.title, "%Mat%")
  RETURN doc.title

Match all titles that end with rix using LIKE():

FOR doc IN imdb
  SEARCH LIKE(doc.title, "%rix")
  RETURN doc.title

Match all titles that have an H as first letter, followed by two arbitrary characters, followed by ry and any amount of characters after that. It will match titles starting with Harry and Henry:

FOR doc IN imdb
  SEARCH LIKE(doc.title, "H__ry%")
  RETURN doc.title

Use a bind parameter as input, but escape the characters with special meaning and perform a contains-style search by prepending and appending a percent sign:

FOR doc IN imdb
  SEARCH LIKE(doc.title, CONCAT("%", SUBSTITUTE(@term, ["_", "%"], ["\\_", "\\%"]), "%"))
  RETURN doc.title

Bind parameters:

{ "term": "y_" }

The query constructs the wildcard string %y\\_% and will match Cry_Wolf.