Updated February 27, 2023
Introduction to Rails Where Method
Any data permanently resides in the database. When data is collected in the database, it may be necessary to retrieve the data and verify it. This process of retrieving the data stored in the database is performed in Rails using the models. So the models are the segments that bind the data in the database to the layer of business where these data are considerably needed. So any process of fetching the data can only be performed using the model screening in the rails method. These models determine the path or the pattern through which the data has to be fetched or placed in the database. Considering the data retrieval part alone, the process can be achieved using several rows pulled from the database. Based on the function used in the active rows, the number of rows to be retrieved will be decided. Where (), find(), and find_by() are the three active record methods that help in retrieving the records. The only significant difference between these is how the values are retrieved or the number of documents retrieved.
How to Use Rails Where Method?
The where() method is used for formulating a query on the active record. This query will be capable of retrieving the information from the database. The query will be able to recover the
Records in the below manner.
Syntax:
Table_Name.where(column_Name1:value1, column_Name2:value2)We can notice from the above syntax how the where clause has been used. The syntax first involves the table name. The table name will be the critical factor here. The table name will mention the database item from which the records must be fetched. This is an essential item. The where clause followed them. The where clause says what type of operation this is going to be. Make it very suitable for the production environment. The source code of the where() will be associated as a gem file; also, a development server comes in associated with a server. This is a development server that helps keep the development process to be very fast this capability. The where() method used with the where clause can retrieve a given set of records from the database. They were followed by the where clause will have the column names and the values associated. The column names have to be given within the open and close braces. The column names must be followed with a colon. Every column name must have a colon used to post and the associated value for which the search is done if more than one value is intended to be searched, then those many column names and the column values have to be given.
How to search function?
As discussed above, the search function in the rails models is used with the means of where clause. The search function helps make the search operation a lot easier. The primary use of the search function is that it allows the search process a much more flexible.
Def search
…..
…..
EndAll search condition values have to be associated with the above-given method. In addition, the route for the searching process has to be added in the erb file associated.
The above-given snapshot has the content of how the search bar looks. We can notice the search field tag is placed between the form tag. So the form tag forms the fields we are discussing, and the form tag will be responsible for setting the search field tag from the front end.
Examples of Rails Where Method
Below are the different examples of Rails Where Method:
Example #1
In the below given example, we are attempting to fetch the record of the name Robert from the database. The query below will fetch the document with the name Robert from the database in the table patient. The where clause mentions what type of operation this will be. Make it very suitable for the production environment. The name will be acting as the column name involved. A patient will be the table name, and Robert will be the value to be fetched.
Query:
Patient.where( Name : " Robert " )
Example #2
In the below given example, we are attempting to fetch the record from an MIS system. The query involves bringing the record from the table with the name book. Then the book’s category and author are the considerations on which the form is attempted to be retrieved. So the intention behind the query is to retrieve a record from the table named book, where the category of the book intended to search falls under the biotechnology category, and the author of the book is categorized under the author name Andrew carnegi. The where clause mentions what type of operation this will be. Make it very suitable for the production environment. The source code of the where() will be associated as a gem file; also, a development server comes in associated with a server. The significant difference between the current and previous queries is the number of parameters passed. In this second example, two different search values have been given for retrieval from the database.
Query:
Book.where( category : " Biotechnology " , author : " Andrew carnegi " )
Conclusion
The above-given article clearly explains the where clause and the syntax behind the process of using the where clause. We also discuss how the where clause has been used and how the value fetching process takes place. The article also discusses the use of the search function and how the search function is used for framing the search bar. The above article discusses two comparative examples of query framing and retrieving the records from the database.
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