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SQL

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Mar 1, 2020

Cards (44)

Section 1

(44 cards)

Read Uncommitted

Front

An ANSI SQL transaction isolation level that allows transactions to read uncommitted data from other transactions, and which allows nonrepeatable reads and phantom reads. The least restrictive level defined by ANSI SQL.

Back

Connected-Architecture

Front

To access connected data you use ADO.NET

Back

Durability

Front

Guarantees that the database will keep track of pending changes in such a way that the server can recover from an abnormal termination.

Back

Read Committed

Front

An ANSI SQL transaction isolation level that allows transactions to read only committed data. This is the default mode of operations for most databases.

Back

ORM

Front

Object Relational Mapping (Database First Approcach)

Back

ACID

Front

ACID (Atomicity, Consistency, Isolation, Durability) ACID (an acronym for Atomicity, Consistency Isolation, Durability) is a concept that Database Professionals generally look for when evaluating databases and application architectures. For a reliable database all these four attributes should be achieved.

Back

DML (Data Manipulation Language)

Front

The portion of SQL, used for querying, inserting, updating, and deleting data from tables. DBMS language that changes database content. (Select, Insert, Update, Delete)

Back

Normalization

Front

The process of applying rules to a database design to ensure that information is divided into the appropriate tables. Main goal is to reduce redundancy.

Back

Disconnected-Architecture

Front

To access disconnected data you do not use ADO.NET. Disconnected-data can be accessed from multiple tables in a dataset.

Back

RIGHT JOIN

Front

The RIGHT JOIN keyword returns all rows from the right table (table2), with the matching rows in the left table (table1). The result is NULL in the left side when there is no match. SELECT column_name(s) FROM table1 RIGHT JOIN table2 ON table1.column_name=table2.column_name;

Back

Union (types)

Front

2 tables are related by their data types. (Union, Union-All, Intersect, Except)

Back

Intersect

Front

The INTERSECT operator is used to combine like rows from two queries. It returns rows that are in common between both results. (Match all records in that record set, matches on the value of that record)

Back

Aggregate

Front

(Average, Count, Sum)

Back

Atomicity

Front

A property of transactions that states that all parts of a transaction must be treated as a single logical unit of work in which all operations must be completed (committed) to produce a consistent database.

Back

UNION ALL

Front

Combine both tables and show all duplicates

Back

LEFT JOIN

Front

The LEFT JOIN keyword returns all rows from the left table (table1), with the matching rows in the right table (table2). The result is NULL in the right side when there is no match. SELECT column_name(s) FROM table1 LEFT JOIN table2 ON table1.column_name=table2.column_name;

Back

Trigger

Front

A SQL trigger is executed or fired whenever an event associated with a table occurs e.g., insert, update or delete. The trigger is special because it is not called directly like a stored procedure.

Back

Database First Approach

Front

Creates the Entity Framework from an existing database. It creates model codes from the database. The database in the project and those classes become the link between the database and controller.

Back

Key

Front

A DBMS key is an attribute or set of an attribute which helps you to identify a row(tuple) in a relation(table). They allow you to find the relation between two tables.

Back

Subquery

Front

An SQL SELECT statement that is inside another select or action query. (CTE, Using-From, Using-Where)

Back

Multiplicity

Front

process by which we increase the level of connectivity between data sets.

Back

SELF JOIN

Front

The process of joining a table to itself.

Back

Join

Front

Matches 2 tables that are related by their keys. (Inner-Join, Left-Join, Right-Join, Full-Join, Cross-Join, Self-Join)

Back

ADO.NET

Front

A data access technology from the Microsoft .NET Framework that provides communication between relational and non-relational systems through a common set of components. ADO.NET is a set of computer software components that programmers can use to access data and data services from a database.

Back

Types of Triggers

Front

(For, After, Instead-Of, Insert, Update, Delete)

Back

INNER JOIN

Front

Only returns matched records from the tables that are being joined

Back

Serializable

Front

An ANSI SQL transaction isolation level that does not allow dirty reads, nonrepeatable reads, or phantom reads; the most restrictive level defined by the ANSI SQL standard.

Back

Repeatable Read

Front

An ANSI SQL transaction isolation level that uses shared locks to ensure that other transactions do not update a row after the original query updates it. However, phantom reads are allowed.

Back

DCL (Data Control Language)

Front

DCL is used to create roles, permissions, and referential integrity as well it is used to control access to database by securing it. Examples: GRANT, REVOKE statements.

Back

RDBMS (Relational Database Management System)

Front

A software application that contains tools to manage data, answer queries, create user-friendly forms for data entry, and generate printed reports. (2 KEY CONCEPTS: NORMALIZATION && MULTIPLICITY)

Back

Atomicity, Consistency, Isolation, Durability

Front

A set of best practices for programmers to seek in all application or data base design

Back

Isolation

Front

Isolation determines how transaction integrity is visible to other users and systems. Keeps transactions separated from each other until they're finished.

Back

FULL JOIN

Front

Return all rows when there is a match in ONE of the tables

Back

Union (def.)

Front

Used to combine the result sets of 2 or more SELECT statements. It removes duplicate rows between the various SELECT statements. Each SELECT statement within the UNION must have the same number of fields in the result sets with similar data types.

Back

SQL broken into these 4 parts

Front

DDL, DML, DCL, TCL (TCL we usually don't worry about, its usually taken care of)

Back

TCL (Transactional Control Language)

Front

Transaction Control Language(TCL) commands are used to manage transactions in the database. These are used to manage the changes made to the data in a table by DML statements. (Commit, Rollback and Savepoint SQL commands)

Back

Except

Front

Used to combine two SELECT statements and returns rows from the first SELECT statement that are not returned by the second SELECT statement. This means EXCEPT returns only rows, which are not available in the second SELECT statement.

Back

Foreign Key (FK)

Front

A foreign key is a column which is added to create a relationship with another table. Foreign keys help us to maintain data integrity and also allows navigation between two different instances of an entity. Every relationship in the model needs to be supported by a foreign key.

Back

Isolation

Front

In database systems, isolation determines how transaction integrity is visible to other users and systems. (Read-Uncommitted, Read-Committed, Repeatable-Read, Serializable)

Back

CROSS JOIN

Front

A join in which each row from one table is combined with each row from another table.

Back

Index

Front

Indexes are special lookup tables that the database search engine can use to speed up data retrieval. Simply put, an index is a pointer to data in a table. An index in a database is very similar to an index in the back of a book.

Back

Consistency

Front

Consistency guarantees that a transaction never leaves your database in a half-finished state.

Back

DDL (Data Definition Language)

Front

A subset of SQL commands used to manipulate Database structures, including tables. (Create, Alter, Drop, Truncate)

Back

Primary Key (PK)

Front

A column or group of columns in a table which helps us to uniquely identifies every row in that table is called a primary key. This DBMS can't be a duplicate. The same value can't appear more than once in the table.

Back