Data Modeling – Flashcards

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False
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The ANSI prescribes a standard SQL the current fully apporved version is known as SQL-07
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True
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The ANSI SQL standards are also accepted by the ISO.
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False
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SQL is considered difficult to learn; its command set has a vocabulary of more than 300 words.
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False
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You cannot insert a row containing a null attribute value using SQL.
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False
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You can select partial table contents by naming the desired fields and by placing restrictions on the rows to be included in the output.
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False
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Oracle users can use the Access QBE (query by example) query generator.
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True
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String comparisons are made from left to right.
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False
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The conditional LIKE must be used in conjuction with wildcard characters.
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True
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Some RDBMSs, such as Microsoft Access, automatically make the necessary conversions to eliminate case sensitivity.
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False
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To join tables, simply enumerate the tables in the FROM clause of the SELECT statement. The DBMS will create a Cartesian product of every table in the FROM clause. To get the correct results, you need to select the rows in which the common attribute values do not match.
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SQL-2003
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The most recent fully approved version of standard SQL prescribed by the ANSI is ___.
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CHAR and VARCHAR
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The SQL character data formats are ___.
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INSERT
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The SQL command that lets you insert rows into a table is ___.
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COMMIT
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The SQL command that lets you insert rows into a table is ___.
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SELECT
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The SQL command that lets you select attributes from rows in one or more tables is ____.
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FORMAT
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In Oracle, the ___ command is used to change the display of a column, for example, to place a $ in front of a numeric value.
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UPDATE
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The SQL command that modifies an attributes values in one or more table's rows is ____.
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subquery
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A ____ is a query that is embedded or nested inside another query.
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ROLLBACK
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The ___ command is used to restore the table's contents to their previous values.
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DELETE
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To delete a row from the PRODUCT table, use the ___ command.
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all rows will be deleted
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When you issue the DELETE FROM tablename command without specifying a WHERE condition, ____.
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alias
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An ____ is an alternate name given to a column or table in any SQL statement.
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IS NULL
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The ____ special operator is used to check whether an attribute value is null.
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LIKE
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The special operator used to check for similar character strings is ____.
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DROP TABLE
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A table can be deleted from the database by using the ___ command.
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COUNT
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The SQL aggregate function that gives the number of rows containing non-null values for a given column is ___.
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AVG
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The SQL aggregate that gives the average for the specific column is ___.
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Schema
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A ___ is a logical group of database objects, such as tables and indexes, that are related to each other.
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CHAR
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U.S. state abbrev. are always 2 characters, so _____ is a logical choice for data type representing a state column.
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ORACLE
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Date & SYSDATE are special functions that return today's date in MA ACCESS AND ___ respectively.
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Reserved Words
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are words used by SQL to perform specific functions.
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Create INDEX
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Using the ___ command, SQL indexes can be created on the basis of any selected attribute.
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attribute names
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In an INSERT command, you can indicate just that attributes that have required values by listing the ___ inside parentheses after the table name.
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wildcard
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A ____ character is a symbol that can be used as a general substitute for other characters or commands.
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Drop TAble
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A table can be deleted from the database by using the ___ command.
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Join
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A ___ is performed when data is retrieved from more than one table at a time.
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recursive
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An alias is especially useful when a table must be joined to itself in a ___ query.
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