Answer Posted / anil

ANS:
COLUMN LEVEL CONSTRAINT
If we provide constraint along with column while creating the table then it is column level constraint. For column level constraint a constraint name is not mandatory.

TABLE(ROW) LEVEL CONSTRAINT
If we provide constraint after providing all the columns then it is table level constraint.For table level constraint a constraint name is mandatory.

Advantage of table level constraint:
We can create composite PK and composite FK in table level constraints but we cant create these in column level constraints.

Example:
CREATE TABLE oracle_tab
(
ord_id  NUMBER,
pid NUMBER,
qty NUMBER(2),
ord_dt DATE NOT NULL, /*column level constraint(cant be created as table level constraint)*/
price NUMBER(9,1) DEFAULT 0, /*column level constraint(cant be created as table level constraint)*/
CONSTRAINT ord_pk PRIMARY KEY(ord_id,pid), /*table level(can be created either as table level constraint or column level)*/
CONSTRAINT ord_fk FOREIGN KEY(pid) REFERENCES products(pid),/*table level(can be created either as table level constraint or column level)*/
CONSTRAINT ord_ch CHECK(qty>0) /*table level(can be created either as table level constraint or column level)*/
);

how to dump a table to a file with 'mysqldump'? : Sql dba

1031

---

What is the current version of postgresql?

1054

---

What is embedded sql what are its advantages?

1030

---

How do I find duplicates in two columns?

1152

---

How does rowid help in running a query faster?

1410

---

Is trigger a stored procedure?

929

---

define data blocks ? : Sql dba

973

---

What is a full join sql?

1051

---

What is sql and how does it work?

1159

---

How do you define a foreign key?

992

---

How can we solve sql error: ora-00904: invalid identifier?

1243

---

Define union, minus, union all, intersect ?

996

---

How do I run a query in pl sql developer?

983

---

What is difference between hql and native sql?

1154

---

What is execute immediate?

1076

---