Skip to main content

Text Index in MongoDB

Text index supports to text search queries on string content. We can any add fields which value is string or an array of string elements.
Text index is introduced in mongodb version 3 but some key features added in mongodb version 3.2, the new features are:

1-   Case sensitive: Previous versions of the text index are case insensitive for [A-z] only; i.e. case insensitive for non-diacritics Latin characters only. For all other characters, earlier versions of the text index treat them as distinct.

2-  Diacritic Insensitivity: There are no facility in index to distinguish between characters that contain diacritic marks and non marks corresponding item for example: é, ê, and e.

3-  Tokenization Delimiters: In previous version text index uses the delimiters categorized under dash and hyphen. For example: if given a string "Il a dit qu'il «était le meilleur joueur du monde»", the text index treats «, », and spaces as delimiters.

Create text index: Suppose we have a collection “Inventory of books”


{"_id":1, "Title":"title1", "Author":"author1", "Publisher":"publisher1", "Qty":10, "Price":20.02}
{"_id":2, "Title":"title2", "Author":"author2", "Publisher":"publisher2", "Qty":12, "Price":26.00}
{"_id":3, "Title":"title3", "Author":"author3", "Publisher":"publisher3", "Qty":14, "Price":20.07}
{"_id":4, "Title":"title4", "Author":"author4", "Publisher":"publisher4", "Qty":11, "Price":243.08}
{"_id":5, "Title":"title5", "Author":"author5", "Publisher":"publisher5", "Qty":14, "Price":202.00}
{"_id":6, "Title":"title6", "Author":"author6", "Publisher":"publisher6", "Qty":16, "Price":102.02}
{"_id":7, "Title":"title7", "Author":"author7", "Publisher":"publisher7", "Qty":13, "Price":130.02}
{"_id":8, "Title":"title8", "Author":"author8", "Publisher":"publisher8", "Qty":15, "Price":233.02}
{"_id":9, "Title":"title9", "Author":"author9", "Publisher":"publisher9", "Qty":16, "Price":244.02}
{"_id":10, "Title":"title10", "Author":"author1", "Publisher":"publisher1", "Qty":17, "Price":250.02}
{"_id":11, "Title":"title11", "Author":"author2", "Publisher":"publisher2", "Qty":13, "Price":260.02}
{"_id":12, "Title":"title12", "Author":"author3", "Publisher":"publisher3", "Qty":13, "Price":267.02}
{"_id":13, "Title":"title13", "Author":"author4", "Publisher":"publisher4", "Qty":12, "Price":288.02}
{"_id":14, "Title":"title14", "Author":"author5", "Publisher":"publisher5", "Qty":14, "Price":286.02}
{"_id":15, "Title":"title15", "Author":"author6", "Publisher":"publisher6", "Qty":16, "Price":50.02}
{"_id":16, "Title":"title16", "Author":"author7", "Publisher":"publisher7", "Qty":17, "Price":60.02}


Create text index using following query


db.books.createIndex( { Title: "text", Author: "text",Publisher:"text" } )


Result:


/* 1 */
{
    "createdCollectionAutomatically" : false,
    "numIndexesBefore" : 1,
    "numIndexesAfter" : 2,
    "ok" : 1.0
}



Note: A collection can have most on text index.

Popular posts from this blog

Add day to ISODate in MongoDB

We can use $add operator to add days in ISODate in mongodb, $add is the Arithmetic Aggregation Operator which adds number and date in mongodb.
Syntax:

{ $add: [ <expression1>, <expression2>, ... ] }

Note:  If one of the argument is date $add operator treats to other arguments as milliseconds to add to the date.
Example: Suppose we have a Test collection as below.

{"Title" : "Add day to ISODate in MongoBD","CreatedDate" : ISODate("2016-07-07T08:00:00.000Z")}

Query to add 2 days in CreatedDate

db.Test.aggregate([      { $project: { Title: 1, AddedDate: { $add: [ "$CreatedDate", 2*24*60*60000 ] } } }    ])

Result:

{ "_id" : ObjectId("579a1567ac1b3f3732483de0"), "Title" : "Add day to ISODate in MongoBD", "AddedDate" : ISODate("2016-07-09T08:00:00.000Z") }

Note: As mentioned in above note we have to convert days in millisecond because $add operator treat to other arg…

What is difference between UNION and UNION ALL in SQL Server

We use UNION and UNION ALL operator to combine multiple results set into one result set.
UNION operator is used to combining multiple results set into one result set but removes any duplicate rows. Basically, UNION is used to performing a DISTINCT operation across all columns in the result set. UNION operator has the extra overhead of removing duplicate rows and sorting result.
UNION ALL operator use to combine multiple results set into one result set but it does not remove any duplicate result. Actually, this does not remove duplicate rows so it is faster than the UNION operator. If you want to combine multiple results and without duplicate records then use UNION otherwise UNION ALL is better.
Following some rules for using UNION/UNION ALL operator
1.The number of the column should be the same in the query's when you want to combine them. 2.The column should be of the same data type. 3.ORDER BY clause can be applied to the overall result set not within each result set.
4.Column name of …

Remove special character from string in MongoDB

Problem: Suppose wehave a collection and one field is type string contains some special character (like !@#$%) and we don’t want these special character.
Solution: We can easily remove the special character from field using script “replace(/[^a-zA-Z 0-9 ]/g, '')” in our query.  How can we remove special character from string using this script please see following example.
Example: Suppose we have a collection “EduSurvey “where we are collecting information from institutions.

{Name:"JB institute”, About:"This is good one collage for MBA", Information:"This $%%institute ##has good faculty etc$$"}
{Name:"MK institute”, About:"This is good one collage for MCA", Information:"This$$%# is the dummy text12"}
{Name:"MG institute”, About:"This is good one collage for B,Tech", Information:"This# institute@ has&* good infrastructure"}

Did you notice Information fields contains some special character so we…