Although not necessary, a naming convention for database objects and data should be established within each organization and should be used consistently. Consistency in naming conventions make data more easily identifiable and data easier to manage in general.
- Data Definition Language (DDL)
- Data Manipulation Language (DML)
- Data Query Language (DQL)
- Data Control Language (DCL)
- Data administration commands (DAC)
- Transactional control commands (TCC)
COMMIT
ROLLBACK
SAVEPOINT
SET TRANSACTIONS
The connection to the database is the main difference. Using the client to connect means you log on to the server directly to access the database. When using the Web, you log on to the Internet to reach the database.
No. If a column is defined as NULL, nothing has to be in the column. If a column is defined as NOT NULL, something does have to be entered.
True, as long as the precision is the correct length.
False. The precision is the total length, where the scale represents the number of places reserved to the right of a decimal point.
No. Most implementations differ in their use of data types. The data types prescribed by ANSI are adhered to but might differ among implementations according to storage precautions taken by each vendor.
DECIMAL(4,2)
DECIMAL(10,2)
DECIMAL(14,1)
DECIMAL(4,2)—Precision = 4, scale = 2
DECIMAL(10,2)—Precision = 10, scale = 2
DECIMAL(14,1)—Precision = 14, scale = 1
Data is a collection of information stored in a database as one of several different data types
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