Database Administration Fundamentals Flashcards
(99 cards)
What is the UNIQUE constraint?
Specifically identifies which column should not contain duplicate values.
What is the CHECK constraint?
Allows the admin to limit the types of data a user can insert into that column of the database.
What is a default constraint?
Used to insert a default value into a column.
What is the NOT NULL constraint?
Requires that data is entered into the cell, it is not allowed to be blank.
What is the primary key?
This uniquely identifies each record in the db.
What is a foreign key?
This is a column in one table that points to the primary key in another table.
Why is it a bad idea to let a foreign key contain a NULL value?
Because it may be impossible to verify the constraints if a foreign key consists of two or more columns if one of them is NULL.
What is a self-reference?
When the foreign key refers to columns in the same table.
What is XQuery?
A query and functional programming language designed to query collections of XML data.
What is SQLCMD?
A command line application that comes with SQL and exposes the management features of SQL Server. It allows SQL queries to be written and executed from the command prompt.
What is TRANSACT-SQL
This is the primary means of programming and managing SQL Server. When you use an DBMS, like SSMS, to perform an action, it is using T-SQL commands in the background to do the work.
What are the three types of files in SQL?
MDF = Primary data files, NDF = Secondary data files and LDF = Log files
Database objects are divided into two categories:
Storage and Programmability
Tables created using the ________ statement are used to store data.
CREATE TABLE
Constraints are also referred to as ____ constraints.
Column
In order to use views, you must use the ______ T-SQL statement to show data from the tables.
SELECT
DDL influences _____, while _______ influences actual data stored in tables.
Database objects, DML
The MS database server that hosts relational databases is called _____
MS SQL Server
The core DDL statements are (6):
ADDUCT: ALTER, DROP, DELETE, USE, CREATE and TRUNCATE
The core DML statements are (5)
MIDUS: MERGE, INSERT, DELETE, UPDATE, SELECT
System views belong to the ______
sys schema
What are 6 constraint types?
Unique, Check, Default, Not Null, Primary Key, Foreign Key
A bit is the T-SQL integer data type that can take a ___ of 1, 0 or NULL.
value
A regular character uses ___ bytes of storage, whereas a unicode character requires ____ bytes.
one, two