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Allows the expression of constraints on domain variables that are either inconvenient or impossible to express within the skeleton tables. ■ Complex conditions can be used in condition boxes ■ Example: Find the loan numbers of all loans made to Smith, to Jones, or to both jointly

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The SQL standard defines embeddings of SQL in a variety of programming languages such as C, Java, and Cobol. ■ A language to which SQL queries are embedded is referred to as a host language, and the SQL structures permitted in the host language comprise embedded SQL. ■ The basic form of these languages follows that of the System R embedding o...

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Find all customers who have an account at all branches located in Brooklyn. select distinct S.customer_name from depositor as S where not exists ( (select branch_name from branch where branch_city = 'Brooklyn') except (select R.branch_name from depositor as T, account as R where T.account_number = R.account_number and S.customer_name = ...

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Aggregation function takes a collection of values and returns a single value as a result. avg: average value min: minimum value max: maximum value sum: sum of values count: number of values ■ Aggregate operation in relational algebra E is any relational­algebra expression ● G 1, G2 , Gn is a list of attributes on which to group (can be em...

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Alternative ways of evaluating a given query ● Equivalent expressions ● Different algorithms for each operation Cost difference between a good and a bad way of evaluating a query can be enormous Need to estimate the cost of operations ● Depends critically on statistical information about relations which the database must maintain ● Need to ...

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The following list describes the basic monitoring tools: Activity Monitor: a tool graphically displays the following information: Processes running on an instance of SQL Server Locks User activity Blocked processes Dynamic management views: return server state information that can be used to monitor the health of a server instance, diagnose ...

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Log shipping is: To send transaction logs from the primary database to the secondary database. To back up the transaction logs from a primary database and then copy and restore them to a secondary database, keep the secondary database nearly synchronized with the primary database. The destination server acts as a backup server. Log shipping ...

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Distributor: Each publisher has a distributor to store replication status data, and metadata about the publication. Sometimes the distributor acts as a data queue for data moving from the publisher to the subscribers and vice versa. There are two types of distributors: local and remote. Local distributor is where the publisher and distribut...

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One of the most important advantages of Database Engine is its capability to automate administrative tasks and hence to reduce costs. Examples of some important tasks that are performed frequently and therefore could be automated: Backing up the database and transaction log Transferring data Dropping and re-creating index Checking data integr...

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SQL Server provides several options for importing XML documents. You can use the OPENROWSET Transact-SQL function to read data, including XML data, from a file. SQL Server also offers many ways to transfer data: OPENXML and XML stored procedures the XML data type’s nodes() method the SQLXML middle-tier API to load XML data as relational data I...

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