AECOM Interview Questions and Answers

To edit in a database with a query, use the UPDATE statement with appropriate conditions and values.

• Use the UPDATE statement to modify data in a database table

• Specify the table name and set the new values using the SET keyword

• Use the WHERE clause to specify the conditions for the update

• Example: UPDATE employees SET salary = 50000 WHERE department = 'IT'

A database is a collection of data that is organized in a way that allows for easy retrieval and manipulation. Keys in a database are unique identifiers for each record.

• A database is used to store and manage data.

• It can be relational or non-relational.

• Keys are used to uniquely identify each record in the database.

• Primary keys are used to identify the main record in a table.

• Foreign keys are used to link tables together.

• Examples of databases include MySQL, Oracle, and MongoDB.

A database is a structured collection of data that is organized and managed to provide efficient retrieval and storage.

• A database is a software system that stores and manages data.

• It provides a way to organize and structure data for easy retrieval and manipulation.

• There are different types of databases, such as relational databases, NoSQL databases, and object-oriented databases.

• Relational databases use tables to store data and have predefined relationships between tables.

• NoS...read more

SQL is a programming language used for managing and manipulating relational databases.

• SQL stands for Structured Query Language.

• It is used to communicate with and manage relational databases.

• SQL can be used to create, modify, and retrieve data from databases.

• There are different types of SQL, such as MySQL, Oracle, SQL Server, etc.

• Common SQL commands include SELECT, INSERT, UPDATE, and DELETE.

• SQL can be used to perform complex queries and join multiple tables.

• It is widely used ...read more

A network is a group of interconnected devices that communicate with each other. There are several types of networks.

• Local Area Network (LAN)

• Wide Area Network (WAN)

• Metropolitan Area Network (MAN)

• Wireless Local Area Network (WLAN)

• Virtual Private Network (VPN)

• Personal Area Network (PAN)

Single phase has one live wire and one neutral wire, while three phase has three live wires and one neutral wire.

• Single phase has a sinusoidal waveform, while three phase has three sinusoidal waveforms with a phase difference of 120 degrees.

• Single phase is commonly used in residential buildings for lighting and small appliances, while three phase is used in industrial applications for heavy machinery and equipment.

• Single phase systems have lower power capacity compared to thr...read more