MongoDB database Data Types

-
MongoDB is a No SQL database that uses document as its data structure to store user's data. MongoDB is a schema-less database in the sense that you do not require to define your fields in advance as well as different structured document can reside in the same collection. This is not possible in case of traditional RDBMS like MySQL, SQL Server, Oracle etc.

A document in MongoDB consists of key value pairs. Keys are written as strings but values can belong to one of the several data types allowed in MongoDB.

Please always refer to the documentation or online resources for your specific version of MongoDB as an application features are always tend to change.

DataType Description
String This commonly used datatype contains a string of text (or any other kind of characters). This datatype is used mostly for storing text values (for example, "Country" : "India"}.
Integer (32b and 64b) This type is used to store a numerical value (for example, { "Rank" : 1 } ). Note that there are no quotes placed before or after the integer.
Boolean This datatype can be set to either TRUE or FALSE.
Double This datatype is used to store floating-point values.
Min/Max keys This datatype is used to compare a value against the lowest and highest BSON elements, respectively.
Arrays This datatype is used to store arrays (for example, ["Membrey, Peter","Plugge,Eelco","Hows, David"]).
Timestamp This datatype is used to store a timestamp. This can be handy for recording when a document has been modified or added.
Object This datatype is used for embedded documents.
null This datatype is used for a Null value.
Symbol This datatype is used identically to a string; however, it’s generally reserved for languages that use a specific symbol type.
Date * This datatype is used to store the current date or time in Unix time format (POSIX time).
Object ID * This datatype is used to store the document’s ID.
Binary Data * This datatype is used to store binary data.
Regular Expression * This datatype is used for regular expressions. All options are represented by specific characters provided in alphabetical order.
JavaScript Code * This datatype is used for JavaScript code.

The asterisks mean that the last five data types (Date, Object ID, Binary Data, Regular Expression and JavaScript Code) are non-JSON types; specifically, they are special data types that BSON allows you to use. You can identify your data types by using the $type operator.

You can embed or reference one document inside another.

Comments

Post a Comment

Back To Top

Popular posts from this blog

error 18 at 0 depth lookup: self signed certificate

-
I was trying to test SSL connection between MySQL client and server. For that I created SSL certificate and keys by following the MySQL documentation at: Creating SSL Certificates and Keys Using openssl After finishing up all the commands when I verify the certificates by using: openssl verify -CAfile ca.pem server-cert.pem client-cert.pem I got the following output: error 18 at 0 depth lookup : self signed certificate error server-cert.pem: verification failed client-cert.pem: OK  Reason : The Common Name value used for the server and client certificates/keys must each differ from the Common Name value used for the CA certificate. Otherwise, the certificate and key files will not work for servers compiled using OpenSSL. Solution : When OpenSSL prompts you for the Common Name for each certificate, use different names. Common Name (e.g. server FQDN or YOUR name) []: I used values as follows: CA Cert:  ssl-ca-cert Server Cert: ssl-ca-server-cert Client Cert:  ssl-c
Read more

How to check fragmentation in MySQL tables

-
MySQL tables, including MyISAM and InnoDB, two of the most common types, experience fragmentation as data is inserted, updated and deleted randomly. Fragmentation can leave large holes in your table, blocks which must be read when scanning the table. Optimizing your table can therefore make full table scans and range scans more efficient. We will mention how to check fragmentation in MySQL tables using SQL queries. USE < put_your_dbname_here > SELECT TABLE_NAME, CONCAT(ROUND(( data_length + index_length ) / ( 1024 * 1024 ), 2), 'M') TOTAL_SIZE, CONCAT(ROUND(( DATA_FREE ) / ( 1024 * 1024 ), 2), 'M') DATA_FREE FROM information_schema.TABLES where table_schema = database() and ROUND(( DATA_FREE ) / ( 1024 * 1024 ), 2) > 0.00 ORDER BY DATA_FREE DESC; SELECT TABLE_NAME, ROUND(((Data_length - (TABLE_ROWS * Avg_row_length))/Data_length) * 100, 2) FRAG_Percent FROM information_schema.TABLES where table_schema = database() and TABLE_ROWS > 0
Read more

How to Drop or Remove or Decommission a Database in Oracle

-
How to Drop or Remove or Decommission a Database in Oracle Database Decommission steps for Oracle 10G and 11g databases Note: ~~~~~~~~ Every organization has its own documented way of removing or decommissioning the active/running database that is supporting an Enterprise’s Application. Here I am presenting some general steps which may coincide with your organization’s standard operation procedure (SOP). 1)   Please get the required approval from Business/Customer to proceed for database decommissioning. 2)   Send the Notification to Business/Customer that we are going to decommission the database. (if required) 3)   Raise a Request for Storage and Backup team to take the required backup (provide all the details in the raised request) and to keep the Backup for a specified period of time, say for next 2 years, (That is called the backup retention period). Retention Period may be varied based on your business needs and SLA. The backup can be on disk or
Read more