BirchStreet Systems Interview Questions and Answers

SQL constraints are rules that are applied to columns in a table to ensure data integrity and consistency.

• SQL constraints are used to enforce rules on the data stored in tables.

• They can be applied to individual columns or the entire table.

• Common types of SQL constraints include primary key, foreign key, unique, not null, and check constraints.

• Primary key constraints ensure that each row in a table is uniquely identifie...read more

Command to create a table and explanation of DDL

• Use CREATE TABLE statement to create a table

• Specify table name and column names with data types

• Add constraints like primary key, foreign key, etc.

• DDL is used to define and modify database objects

• Examples: CREATE TABLE customers (id INT PRIMARY KEY, name VARCHAR(50));

• DDL includes CREATE, ALTER, DROP, TRUNCATE statements

Clause types are used in grammar to categorize sentences based on their structure and purpose.

• There are four main types of clauses: independent, dependent, relative, and noun clauses.

• Independent clauses can stand alone as a sentence, while dependent clauses cannot.

• Relative clauses provide additional information about a noun or pronoun in the sentence.

• Noun clauses function as a noun in the sentence.

• Clauses can be used t...read more