[ad_1] Kubernetes is almost everywhere. Transactional applications, movie streaming services, and device studying workloads are acquiring a household on this at any time-escalating platform. But what about databases? If you experienced requested me this question five decades ago, the response would have been a resounding “No!” — based on my practical experience in growth and … Read more
[ad_1] The dreaded portion of each individual internet site trustworthiness engineer’s (SRE) career inevitably: capability setting up. You know, the dance involving all the stakeholders when deploying your apps. Did engineering seriously simulate the suitable load and do we comprehend how the software scales? Did item managers accurately estimate the volume of use? Did we … Read more
To handle tasks, like to store multiple elements, collections are used in Cassandra. Collection can be of three types in Cassandra: Set, List or Map Set: It stores a group of elements. Sorted elements are returned when querying. Example: Creating a table: Create table volunteers ( id int, email set<text>, Primary key(id) );Creating a table: … Read more
To delete data from a table in Cassandra, the DELETE command is used. Syntax: DELETE FROM <identifier> WHERE <condition>;DELETE FROM <identifier> WHERE <condition>; Example 1: Delete an entire row. Employees table: id name salary 1 Adi 50000 2 Bruno 30000 3 Chris 60000 4 Davis 20000 5 Eliza 15000 Query: DELETE FROM employees WHERE id … Read more
To update data in a table in Cassandra, the UPDATE command is used. Keywords: WHERE clause: Used to select the row to be updated. SET clause: Used to set the value. MUST clause: Used to include all the columns composing the primary key. Syntax 1: UPDATE <table_name> SET <column_name> = <new_value> <column_name> = <value>…. WHERE … Read more
To read data from a table in Cassandra, the SELECT command is used. Syntax 1: SELECT FROM <table_name>SELECT FROM <table_name> Syntax 2: Using WHERE clause. SELECT FROM <table name> WHERE <condition>;SELECT FROM <table name> WHERE <condition>; Example 1: SELECT * FROM employees;SELECT * FROM employees; Output: id name salary 1 Adi 50000 2 Bruno 30000 … Read more
To insert data into the columns of a table in Cassandra, the INSERT command is used. Syntax: INSERT INTO <table_name> (<column1_name>, <column2_name>….) VALUES (<value1>, <value2>….) USING <option>INSERT INTO <table_name> (<column1_name>, <column2_name>….) VALUES (<value1>, <value2>….) USING <option> Example: INSERT INTO employees<id, name, salary> values<1, ‘Adi’, 50000>; INSERT INTO employees<id, name, salary> values<2, ‘Bruno’, 30000>; INSERT INTO … Read more
We can execute multiple modification statements simultaneously in Cassandra, whether it is an insert, update or delete statement. Syntax: BEGIN BATCH <insert-stmt>/ <update-stmt>/ <delete-stmt> APPLY BATCHBEGIN BATCH <insert-stmt>/ <update-stmt>/ <delete-stmt> APPLY BATCH Example: Employees table: id name salary 1 Adi 50000 2 Bruno 30000 3 Chris 60000 4 Davis 20000 5 Eliza 15000 Query: BEGIN … Read more
Cassandra DROP Index To drop a specified index in Cassandra, the DROP INDEX command is used. The index name is TableName_ColumnName_idx, in case if the index name was not specified during index creation. Syntax 1: DROP INDEXDROP INDEX Syntax 2: Drop index IF EXISTS Keyspace_Name.Index_NameDrop index IF EXISTS Keyspace_Name.Index_Name Important Points: An error will be … Read more
Cassandra Create Index We can create an index in Cassandra, on the column specified by the user, by using the CREATE INDEX command. Indexes are created on the data if the data already exists for the selected column. Syntax: CREATE INDEX indexIdentifier ON tablename Important Points: The primary key in Cassandra is already indexed and … Read more