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- 1What is a DBMS?Program that controls creation, maint, and use of a database
- 2What is RDMBS?Relation Database Management System - stores data in collection of tables that are related by common fields among them
- 3What is SQL?Structured Query Language - communicates with database and performs tasks that create, read, update, and delete
- 4What is a database?Organized for of data for easy access, storing, retrieval and management of data
- 5What are tables and fields?Table is a set of data organized in columns and rows. Each column is a field
- 6What is a primary key?combination of fields that uniquely specifies a row. NOT NULL constraint?
- 7What is a unique key?Provides uniqueness for column or set of columns. There can be many unique keys in a table but only one primary key
- 8what is a foreign key?can be related to the primary key of another table when relationship is needed between two or more tables
- 9What is a join?query data from more than one table
- 10What is an inner join?returns rows when there is at least one match of rows between the tables
- 11What is a right join?Right join will always return all rows of right table and any matches from the left
- 12what is a left join?Left join returns rows common between the tables and all rows of left hand side table
- 13what is a full join?Returns rows when there are matching rows in any one of the tables
- 14What is normalization?process of minimizing redundancy and dependencies in a database. Try to add, delete, or modify any field that can be made in a single table
- 15What is a view?a virtual table that has a subset of data. Takes less space to store
- 16What is an index in a database?Index is used for performance tuning allowing faster retrieval of records from table. Creates entry for each value
- 17What is a database cursor?a control that traverses over the rows or records in the table. Used for retrieval, addition, and removal of database records
- 18What are the relationships in a database?Connections between tables
One to One
One to Many
Many to One - 19What is a query?code written to get information back from the database, essential a question
- 20What is a subquery?a query within a query. Subquery is always executed first
- 21What is a stored procedure?a function that consists of many SQL statements to access the database.
- 22What's the difference between DELETE and TRUNCATEdelete removes all rows and can use where to set parameters. Truncate removes all rows from table and cannot be rolled back
- 23What is a contraint?Contraint specifies the limit on the data type of a table
NOT NULL
CHECK
DEFAULT
UNIQUE
PRIMARY KEY
FOREIGN KEY - 24What is data integrity?Defines the accuracy and consistency of data stored in a database. Define business rules on the data when it's entered
- 25What is user defined functions?Functions written to use logic wherever required.
- 26What are all types of user defined functions?Scalar - returns unit
Inline table value - table
Multistatement valued - table - 27Advantages and disadvantages of Stored ProceduresCreate once and store to be used everywhere.
Can only be executed in the Database and utilizes more memory in the database server - 28What is Online Transaction ProcessingServing real time transactions
- 29what is a SQL clause?defined to limit the result by providing condition to the query
- 30What is a UNION in SQL?Combine rows from both queries
- 31What is an INTERSECT in SQL?combine only rows in common between queries
- 32What is EXCEPT in SQL?Keep rows from left query that aren't include in the second query
- 33What is the difference between SQL TRUNCATE and DROP?Truncate removes all rows, drop removes table from the database
- 34How to create empty table from exisiting table?Select * INTO FROM xxxx WHERE xxxx
- 35How to retrieve common records from two tables?SELECT xxxx FROM xxxx INTERSECT xxxx FROM xxxxx
- 36How to select unique records from a table?SELECT DISTINCT xxx, xxx,xxx FROM xxxx
- 37What is the commond to get first 5 characters of string in SQLSELECT SUBSTRING(field, startingIndex, endingIndec) as newFieldName from Table
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- SQL Interview Questions Fichas sobre Sin título, creado por Jesse Roy el 02/08/2018.
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- Jesse Roy
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