What are primary keys and foreign keys?
Answers were Sorted based on User's Feedback
Answer / nevual
Primary keys are the unique identifiers for each row. They
must contain unique values and cannot be null. Due to their
importance in relational databases, Primary keys are the
most fundamental of all keys and constraints. A table can
have only one Primary key.
Foreign keys are both a method of ensuring data integrity
and a manifestation of the relationship between tables.
| Is This Answer Correct ? | 7 Yes | 0 No |
Answer / sudarsan
Primary key is a unique id for each table. This prevents
duplication of records. Each table can have a single
primary key. They can be refrenced by any tables as a
foreign key.
| Is This Answer Correct ? | 4 Yes | 0 No |
Answer / jai prakash chauhan
Primary keys are by default clustered index.
| Is This Answer Correct ? | 3 Yes | 2 No |
• Primary Key: A unique identifier for a table’s record (e.g., id in a table).
• Foreign Key: A column in a table that refers to the primary key of another table, establishing a relationship between tables.
| Is This Answer Correct ? | 0 Yes | 0 No |
What is a covered index?
Explain having clause and where clause?
How to insert and update data into a table with "insert" and "update" statements?
What is the difference between DTS and SSIS?
explain the type of contraints
here id col have primary key and identity id name 1 a 2 b 3 c 4 d delete 2nd row then o/p will be id name 1 a 3 c 4 d next inssert 2nd row and i want o/p will be id name 1 a 2 e 3 c 4 d
What is create statement?
what are the joins,primary key,foriegn key, candidate key, super key and expain them?
How do I view views in sql server?
hi, the following are the outputs of sp_spaceused and sp_tempdbspace sp_spaceused ------------ database size unallocated size tempdb 77752.95 MB 28026.99 MB sp_tempdbspace ------------- database size spaceused tempdb 77752.945312 1.007812 the unused space in sp_spaceused is nearly 28 Gb and in sp_tempdbspace is nearly 76 Gb cany any one explain about this output and why its giving different results.
What is difference between stored procedure & function?
3 Answers CarrizalSoft Technologies, Concept Infoway, TATA,
Explain what is the difference between union and union all?
Oracle (3259)
SQL Server (4518)
MS Access (429)
MySQL (1402)
Postgre (483)
Sybase (267)
DB Architecture (141)
DB Administration (291)
DB Development (113)
SQL PLSQL (3330)
MongoDB (502)
IBM Informix (50)
Neo4j (82)
InfluxDB (0)
Apache CouchDB (44)
Firebird (5)
Database Management (1411)
Databases AllOther (288)