Pregunta 1
Pregunta
What are the essential properties of transactions?
Respuesta
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Atomicity
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Durability
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Consistency
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Manageability
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Isolation
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Co-operativity
Pregunta 2
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A database that's gone through how many normalization forms is usually considered "good enough"?
Pregunta 3
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What are the benefits of stored procedures?
Pregunta 4
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What are the types of triggers?
Respuesta
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INSTEAD OF
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DELAYED
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BEFORE
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AFTER
Pregunta 5
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Triggers take part in transactions.
Pregunta 6
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Changes to table variables within a scope of a transaction get rolled back when the transaction is rolled back.
Pregunta 7
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One should prefer using CHECK constraints to triggers.
Pregunta 8
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DDL triggers are always AFTER triggers.
Pregunta 9
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It's best practice to build views from other views. This promotes code reuse.
Pregunta 10
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Some views can be used to update underlying tables.
Pregunta 11
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Some views with aggregate functions in them can be used to update the underlying table(s).
Pregunta 12
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An indexed view materializes data in the I/O subsystem and requires a clustered index.
Pregunta 13
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Heaps are tables without a clustered index on them.
Pregunta 14
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It's best practice to put clustered indexes on all tables, even the small ones.
Pregunta 15
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The SCHEMABINDING option used with a view prevents schema changes to any underlying tables.
Pregunta 16
Pregunta
What is the main benefit of using an index on a table?
Respuesta
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It prevents updating table statistics too frequently.
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It stores the data in the table in an ordered state.
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It makes writing queries easier.
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It helps locate rows more quickly and efficiently.
Pregunta 17
Pregunta
For all intents and purposes, is a clustered index the same as the table itself?
Pregunta 18
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You should always write queries in a way that takes advantage of set-based operations and avoid cursors.
Pregunta 19
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A linked server configuration enables SQL Server to exec commands against an OLE DB data sources on remote servers.
Pregunta 20
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A subquery can be used anywhere an expression can be used.
Pregunta 21
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An INNER JOIN will always return at least one row of data.
Pregunta 22
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It's best practice to always use LEFT OUTER JON instead of RIGHT OUTER JOIN and these two should not be used in the same query for the sake of clarity and ease of understanding.
Pregunta 23
Pregunta
If two tables, [A] with m rows and [B] with n rows, are CROSS JOINed, the result set has how many rows?
Respuesta
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m + n - 1
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m * n - 1
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m * n
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( m - 1 ) * ( n - 1 )
Pregunta 24
Pregunta
In a FULL OUTER JOIN all of the rows of all of the joined tables are included, whether they are matched or not.
Pregunta 25
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If you SELF JON a table, you have to use table aliases.
Pregunta 26
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What are the types of SQL user-defined functions?
Pregunta 27
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An inline table-valued function is the best type of function from the point of view of function performance.
Pregunta 28
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Multi-statement table-valued functions can have side-effects (e.g., update a table).
Pregunta 29
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You can insert data returned straight from a stored procedure by using the INSERT...EXEC statement.
Pregunta 30
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An identity field can temporarily be disabled (for instance, during a data load) by using one of the SET directives.
Pregunta 31
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When a table is truncated, an identity field is reset to its starting value.
Pregunta 32
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When all the rows in a table are DELETEd, the identity column gets reset to its initial value.
Pregunta 33
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Every table should have a primary key constraint to uniquely identify each row and only one primary key constraint can be created for each table.
Pregunta 34
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It is possible to change the length of a column defined as a PRIMARY KEY constraint without first deleting it and then re-creating it.
Pregunta 35
Pregunta
Which constraint enforces referential integrity?
Respuesta
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UNIQUE KEY constraint
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FOREIGN KEY constraint
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CHECK constraint
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TRIGGER
Pregunta 36
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A CHECK constraint does not come into play if the relevant column receives a NULL value.
Pregunta 37
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One should always prefer CHECK constraints to TRIGGERS.
Pregunta 38
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The UNIQUE constraint is always implemented as a unique index on the relevant column(s).
Pregunta 39
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What is the outcome of the expression under the default settings of SQL Server: SELECT ( 'a' + NULL ) ?
Respuesta
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a
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NULL
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an error is returned
Pregunta 40
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It is best practice not to use query/table hints in production code due to maintenance issues.
Pregunta 41
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Which WHERE clause has the potential to benefit from an index?
Respuesta
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WHERE Firstname LIKE '%N'
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WHERE Firstname LIKE 'N%'
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WHERE Firstname LIKE '%N%'
Pregunta 42
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BCP lets one perform data imports and exports using a command-line utility.
Pregunta 43
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Dirty reads can happen if you use the isolation level of READ COMMITTED.
Pregunta 44
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The SERIALIZABLE isolation level is sufficient to ensure that no phantom rows appear within a transaction.
Pregunta 45
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It is best practice to set FILLFACTOR to 100 (or 0) on an index in a read-only table.
Pregunta 46
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The DENY permission takes precedence over all other permissions that a user might have for an object.
Pregunta 47
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A lock can go from the row level to the page level.
Pregunta 48
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The DELETE command has much more overhead in terms of log activity than TRUNCATE.
Pregunta 49
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It is best practice to specify collation inline within a query.
Pregunta 50
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The collation of a SQL Server can be changed without re-installation once the server has been installed.
Pregunta 51
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The SNAPSHOT isolation level relies heavily on tempdb.
Pregunta 52
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It is best practice to have a clustered index on a column against which range searches/scans are performed.
Pregunta 53
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To improve performance of a view one can try to convert it into an indexed view.
Pregunta 54
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A stale statistics can lead to the optimizer's not picking up an optimal query plan and underestimation of row counts.
Pregunta 55
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Statistics can be created manually and automatically by SQL Server.
Pregunta 56
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When a statistics is updated with the FULLSCAN option, it means that SQL Server will use data across all the rows to infer the distribution of values in the relevant column(s).
Pregunta 57
Pregunta
What is the outcome of the following query: SELECT 1 WHERE ( 1 = 0 )?
Respuesta
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1
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0
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NULL
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empty set (no rows)
Pregunta 58
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Does the ORDER BY clause paired with TOP(100 PERCENT) used in a view guarantee the order of the returned rows?
Pregunta 59
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If you use ORDER BY in a query, what you really get is not a relational set but a cursor.
Pregunta 60
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It is best practice to use UNION ALL wherever possible instead of UNION due to performance reasons.
Pregunta 61
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A deadlock can happen if two pieces of code access the same objects in reverse order at the same time.
Pregunta 62
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Deadlock is a blocking situation but a blocking situation doesn't necessarily have to be a deadlock.
Pregunta 63
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It is best practice to always use UNICODE data types (for textual values) regardless of whether the data comes from a UNICODE source or not.
Pregunta 64
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It is best practice to always store integers as BIGINTs because this frees the developer from thinking about the smallest data type there could be to accommodate all the anticipated values.
Pregunta 65
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The XML data type in SQL Server can be tied to an XML schema but this is not required.
Pregunta 66
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The EXCEPT operator removes all duplicates from the result set and treats two NULL values as being equal.
Pregunta 67
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In the new error-handling construct, TRY...CATCH, it is possible to use the FINALLY block known from other languages.
Pregunta 68
Pregunta
What does the SET XACT_ABORT ON; directive do?
Respuesta
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It ensures that the isolation level of the code following it cannot be changed without raising an error.
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It ensures that the developer must handle any rollbacks manually.
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It ensures that a transaction is aborted without a rollback when an error is encountered and SQL Server raises error 825 (written to the error log).
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It ensures that a transaction is automatically rolled back if an error occurs.
Pregunta 69
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A table-valued variable can be used as an argument to a stored procedure only if it matches a user-defined table type and is marked as READONLY.
Pregunta 70
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A subquery can contain an ORDER BY clause.
Pregunta 71
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To return de-normalized data from a table/tables one can use the PIVOT operator.
Pregunta 72
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To how many levels can you nest stored procedures (and managed code)?
Pregunta 73
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You can only have one PRIMARY filegroup per database but as many user-defined filegroups as you want.
Pregunta 74
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It is best practice to only have one log file per database.
Pregunta 75
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Data is written to a log file in a sequential manner.
Pregunta 76
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Log files can be placed into filegroups in much the same way as data files can.
Pregunta 77
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It is best practice to always qualify the name of any object by the containing schema because this saves SQL Server the time it needs to look for this object otherwise.
Pregunta 78
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One can put a non-clustered index an a heap or on a clustered table.
Pregunta 79
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PowerShell cannot be used to change the collation of a server.
Pregunta 80
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PowerShell can execute any SQL query against a SQL Server database.
Pregunta 81
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It is best practice to prefer using ORs to ANDs when building queries.
Pregunta 82
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One can configure log-shipping in such a way that the database to which logs are being shipped is usable for reporting purposes.
Pregunta 83
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What's the outcome of the following: IF ( SELECT 1/0 WHERE ( 1 = 0 ) ) IS NULL PRINT 'A' ELSE PRINT 'B'; ?
Pregunta 84
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Temporary tables can have indexes defined on them and SQL Server can create statistics on them when it deems it appropriate.
Pregunta 85
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A table variable can be pushed out to tempdb.
Pregunta 86
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Parallel query execution plans are always better in terms of performance than single-threaded plans.
Pregunta 87
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SQL Server supports directly a many-to-many relationship between tables.
Pregunta 88
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CHECKPOINTS truncate the log when the database is in the FULL recovery model.
Pregunta 89
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SQL Server supports regular expressions out-of-the-box.
Pregunta 90
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Cardinality issues stem from the fact that statistics are stale and they almost always lead to the optimizer choosing suboptimal query execution plan.
Pregunta 91
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A non-clustered index and tempdb can be created on a separate (physical) drive to improve performance.
Pregunta 92
Pregunta
Which aggregate function(s) do(es) ignore NULLs?
Pregunta 93
Pregunta
Do you have to take a database offline to change the physical location of one of its files?
Pregunta 94
Pregunta
Can we insert data into a table on which the clustered index has been disabled?
Pregunta 95
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It is best practice to use the WITH RECOMPILE directive for a stored procedure that will be executed infrequently and the data distribution in the table(s) it uses is very different for different parameters.
Pregunta 96
Pregunta
Which is the preferred way of checking if a table is not empty:
1) ( SELECT COUNT(*) FROM dbo.Table ) > 0
2) EXISTS ( SELECT * FROM dbo.Table )
3) ( SELECT MAX( [ColumnName] FROM dbo.Table ) IS NOT NULL
Pregunta 97
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SELECT...INTO will never lock system objects.
Pregunta 98
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Does the order of columns in UPDATE statements matter in any way?
Pregunta 99
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What are the special memory resident tables available when dealing with triggers?
Pregunta 100
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User-defined functions can raise errors inside their bodies the same way stored procedures can by calling the RAISERROR function.
Pregunta 101
Pregunta
In which database is the metadata about SQL Server Agent jobs stored?
Respuesta
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master
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tempdb
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msdb
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resource
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model
Pregunta 102
Pregunta
Which database(s) should a DBA back up on a regular schedule?
Pregunta 103
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The fastest way to improve a performance of a SELECT query is to add a covering index to the table(s).
Pregunta 104
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Transactions can span multiple batches, that is, pieces of code separated by GO.
Pregunta 105
Pregunta
Activity Monitor lets you see in real-time the most expensive queries executing on the machine.
Pregunta 106
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It is best practice not to use Common Table Expressions as they usually perform much worse than plain subqueries.
Pregunta 107
Pregunta
Which function returns data with greater resolution?
Pregunta 108
Pregunta
Is it true that errors whose severity level is below 11 cannot be handled by the TRY...CATCH construct?
Pregunta 109
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Can the TRY...CATCH block catch object name resolution errors?
Pregunta 110
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Does SELECT...INTO transfer indexes to the new table?
Pregunta 111
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Is it true that each and every user in a database is automatically a member of the public role?
Pregunta 112
Pregunta
Can the dbo user in a database be denied access to a table?
Pregunta 113
Pregunta
When data is deleted from a table, SQL Server immediately reduces the size of the table.
Pregunta 114
Pregunta
Which functions operate on the XML data type in SQL Server?
Respuesta
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query()
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value()
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exists()
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is()
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modify()
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nodes()
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length()
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datatype()
Pregunta 115
Pregunta
In which system database are usernames and passwords (if any) stored?
Respuesta
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model
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msdb
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master
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distribution
Pregunta 116
Pregunta
Which are good properties of a clustered index?
Respuesta
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Static
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Narrow
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Ever-increasing
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Random
Pregunta 117
Pregunta
It is best practice to shrink log files on a regular basis.
Pregunta 118
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Only a log backup can clear the log of inactive transactions and make space inside it reusable when the recovery model of a database is FULL or BULK_LOGGED.
Pregunta 119
Pregunta
How many different database recovery models does SQL Server support?
Pregunta 120
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Online index rebuilds are available in all editions of SQL Server except the Express one.
Pregunta 121
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What's the outcome of the query: SELECT COALESCE(NULLIF(1, 1), 'A')?
Pregunta 122
Pregunta
Which process is the CXPACKET wait type associated with?
Respuesta
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Reading data from disk to cache
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Executing parallel query plans
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Flushing dirty pages to disk
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Receiving asynchronous messages via SQL Server Broker
Pregunta 123
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It is best practice to not create indexes on foreign key columns.
Pregunta 124
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It is best practice not to give objects names that contain special characters or spaces.
Pregunta 125
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It is best practice to turn off the AUTO CREATE and AUTO UPDATE of statistics and take care of them manually.
Pregunta 126
Pregunta
Which one is the preferred way of capturing the last inserted identity value in a session?
Respuesta
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@@Indentity
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SCOPE_IDENTITY()