Filter
Top Products
Table declaration
A table declaration declares the schema in which a table is located. If a table declaration is specified, the schema
name need not be specified for a table in data manipulation statements. Using a table declaration simplifies the
specification of table names. Using a table declaration also helps to make an application program independent of a
data base.
Table name
A name attached to table. Table names are set in schema definitions. Table names are used to specify the tables to be
made the subjects of operations in SQL statements that manipulate data.
Temporary table
A table created specifically for a user of an application program. Multiple users can use temporary tables with the
same table name. To temporarily save data being processed by an application program, a temporary table can be
used independently of other application programs.
Transaction
The unit that guarantees consistency of sequential data operations. A database can be accessed and updated serially
or updated by arranging a number of SQL statements. If a problem such as an unexpected system crash occurs
during sequential data operations, database recovery status can be based on units of transactions.
Trigger definition
Trigger definition defines table data manipulation (insert) in conjunction with other table data manipulations (insert,
delete, update).
Unique constraint
A constraint on a table or column. This constraint requires that a table cannot have multiple rows having the same
value in a column or combination of columns.
Updatable cursor
In an SQL data manipulation statement, a cursor that can be used to update and delete is called an updatable cursor.
The cursor declaration specifies whether a cursor is updatable. For example, if a table specified in the FROM clause
of a query specification satisfies just one condition, the cursor is an updatable cursor.
Related terms:
Read-only cursor
Update mode
A mode denoting strength of exclusion. Also called nonshared mode, the update mode represents the strength of data
locks in data manipulation. Data that is locked in update mode cannot be manipulated by other transactions. In
general, the execution of other transactions waits until a commit is performed on the transaction that obtained the data
lock.
217