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SQL Server Interview Questions :two: - Coggle Diagram
SQL Server Interview Questions :two:
subquery
SELECT
INSERT
UPDATE
DELETE
key :key:
unique
columns ID
multiple
nullable :zero:
primary
rows ID
just 1
not null
foreign
field
links
PK
Unique key
Referential Integrity :scroll:
rules
enforce
table relationships :family:
through
FK
triggers
check constraints
aims
DB consistence
ER diagram
visual representation
tables
relationships
displays
Check Constraints
limit values :no_entry:
N to 1 column
1 to N columns
SQL injection 💉
attack :fist-2:
usually through strings
SQL server
😱 executes it
SQL statements
:check: verified
DB Mirroring
1 DB
2 copies
different locations
safer
Query types
Update ✏
UPDATE…SET
multiple rows
Select
🔎 retrieves data
Delete
Make table
SELECT…INTO
Insert
results
INSERT INTO…SELECT
copy
in table
among tables
values
INSERT INTO…VALUES
JOIN
min tables
types
INNER
common data
LEFT/RIGHT
complete records
left table
right table
FULL
all tables
all matched records
