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quick quesions

Posted on 2011-03-12
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Hi all,
 I have some quick questions about database knowledge:
       1. main data object of relational database, which one: column, row, table, field?
       2 . table field may or may not have a value: true or false?
       3. all rows of table has same structure: true or false?
       4. all column of a table must have a name: true or false?
       5. name of column of table must be unique :true or false
        6. row of table must be unique: true or false
        7 row of table should be unique : true or false

thanks a lot.
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Question by:BeginToLearn
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Accepted Solution

by:
Dave Baldwin earned 1400 total points
ID: 35117178
1. table
2. it depends, a field can be defined as 'not null' and require a value
3. true
4. true - part of the definition of the column
5. true within that table
6. false
7. true
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Author Comment

by:BeginToLearn
ID: 35117197
please verify those:

A table is horizontally structured into column and vertically into row --> False??

Information should have one standard definition and presentaion , unless compelling business differences dictate otherwise---> True??

tks.
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Assisted Solution

by:sihar86
sihar86 earned 600 total points
ID: 35117208
1. main data object of relational database, which one: column, row, table, field?
column, ex: bookid column in borrowing table reference to bookid column in book table
       
2 . table field may or may not have a value: true or false?
true: we usually call it null, right?

3. all rows of table has same structure: true or false?
true (since table consists of many rows that have same column pattern)

4. all column of a table must have a name: true or false?
true

5. name of column of table must be unique :true or false
true

6. row of table must be unique: true or false
false

7 row of table should be unique : true or false
true
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LVL 83

Expert Comment

by:Dave Baldwin
ID: 35117236
A table is normally represented like a spreadsheet.  Rows are horizontal and columns are vertical.

"Information should have one standard definition and presentation" is basically true.  It would be confusing otherwise.
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Author Comment

by:BeginToLearn
ID: 35117260
main data object of relational database, which one: column, row, table, field?
table vs column?
 I think it should be table right? because table is the key to make database difference in compared with datastructure??
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Author Comment

by:BeginToLearn
ID: 35117285
hi angel,
 I just wonder whether i can ask those question in summary after reading each chapter to verify my understanding?  
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Author Comment

by:BeginToLearn
ID: 35117345
Tks.i get it clear now :)
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