Structured Query Language (SQL) (AQA GCSE Computer Science): Flashcards
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SQL data manipulation three operations
SQL data manipulation three operations
Add new records, modify existing ones, remove unwanted data
Three essential SQL data manipulation commands
Three essential SQL data manipulation commands
INSERT, UPDATE, DELETE
Purpose of INSERT command
Purpose of INSERT command
Adds brand new rows of data to an existing table
Basic INSERT syntax structure
Basic INSERT syntax structure
INSERT INTO table (fields) VALUES (values)
INSERT requirement for fields and values
INSERT requirement for fields and values
Must match up perfectly (first value to first field, etc.)
Purpose of UPDATE command
Purpose of UPDATE command
Modifies existing records without deleting and recreating them
Three key parts of UPDATE command
Three key parts of UPDATE command
Table to update, SET clause, WHERE clause
Role of WHERE clause in UPDATE
Role of WHERE clause in UPDATE
Specifies exactly which records should be modified
Result of UPDATE without WHERE clause
Result of UPDATE without WHERE clause
Changes every single record in the table
Purpose of DELETE command
Purpose of DELETE command
Removes unwanted records permanently from database
Basic DELETE syntax structure
Basic DELETE syntax structure
DELETE FROM table_name WHERE condition
Result of DELETE without WHERE clause
Result of DELETE without WHERE clause
Deletes every single record in the table
Most dangerous SQL command
Most dangerous SQL command
DELETE (permanently removes data)
WHERE clause role as safety feature
WHERE clause role as safety feature
Acts as filter ensuring only specific records are affected