 Related Questions The data dictionary of an ORACLE database is a set of tables and views that are used as a read-only reference about the database.It stores information about both the logical and physical structure of the Latest Answer : Data Dictionary is a read-only set of tables that provides information about the database. in order to avoid the I/O cost, these data dictionary views are used ... An integrity constraint is a declarative way to define a business rule for a column of a table. Latest Answer : Special requirements for table data:1) allow NULL value2) uniqueness of value3) primary key4) foreign key5) special value size/text/length etc requirementsAll information is stored in Data Dictionary. ... Can an Integrity Constraint be enforced on a table if some existing table data does not satisfy the constraint ? No. NOT NULL Constraint - Disallows Nulls in a table's column.UNIQUE Constraint - Disallows duplicate values in a column or set of columns.PRIMARY KEY Constraint - Disallows duplicate values and Nulls A column defined as UNIQUE can contain Nulls while a column defined as PRIMARY KEY can't contain Nulls. Latest Answer : A table can have any number unique keys but a single primary key ... A rule defined on a column (or set of columns) in one table that allows the insert or update of a row only if the value for the column or set of columns (the dependent value) matches a value in a column Latest Answer : Referential integrity is a relationship between two tables, one being the 'parent' and the other being the 'child'. The 'child' table references values in the 'parent' table's primary key to ensure all data between ... UPDATE and DELETE Restrict - A referential integrity rule that disallows the update or deletion of referenced data.DELETE Cascade - When a referenced row is deleted all associated dependent rows are deleted. Latest Answer : Foreign key value must exist as PK value on some other  table...FK value can be null but PK can't ... If a foreign key reference a parent key of the same table is called self-referential integrity constraint. Latest Answer : Self referential integrity constraint refers to two columns related by referential integrity which belong to the same table.For example ManagerId column in employees table is a foreign key which refers to EmployeeId in the same table. ... The condition must be a Boolean expression evaluated using the values in the row being inserted or updated and can't contain sub queries, sequence, the SYSDATE,UID,USER or USERENV SQL functions, or Latest Answer : A check constraint allows you to specify a condition on each row in a table. Note: A check constraint can NOT be defined on a VIEW. The check constraint defined on a table must refer to only columns in that table. It can not refer to columns in other ... Latest Answer : Blob datatype is used for storing large Binary data Like Photos,signatures etc Clob datatype is used for stoeing large character data upto 4GB like resume and other docs ...
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