数据管理员面试常见七个问题
<p>数据管理员面试常见七个问题</p><p>1. <span word="Why">Why</span> <span word="is">is</span> <span word="a">a</span> <span word="UNION">UNION</span> <span word="ALL">ALL</span> <span word="faster">faster</span> <span word="than">than</span> <span word="a">a</span> <span word="UNION">UNION</span>?</p><p><span word="The">The</span> <span word="union">union</span> <span word="operation">operation</span>, <span word="you">you</span> <span word="will">will</span> <span word="recall">recall</span>, <span word="brings">brings</span> <span word="two">two</span> <span word="sets">sets</span> <span word="of">of</span> <span word="data">data</span> <span word="together">together</span>. <span word="It">It</span> <span word="will">will</span> <span word="not">not</span>, <span word="however">however</span>, <span word="produce">produce</span> <span word="duplicate">duplicate</span> <span word="or">or</span> <span word="redundant">redundant</span> <span word="rows">rows</span>. <span word="To">To</span> <span word="perform">perform</span> <span word="this">this</span> <span word="feat">feat</span> <span word="of">of</span> <span word="magic">magic</span>, <span word="a">a</span> <span word="SORT">SORT</span> <span word="operation">operation</span> <span word="is">is</span> <span word="done">done</span> <span word="on">on</span> <span word="both">both</span> <span word="tables">tables</span>. <span word="This">This</span> <span word="is">is</span> <span word="obviously">obviously</span> <span word="computationally">computationally</span></p><p><span word="intensive">intensive</span>, <span word="and">and</span> <span word="uses">uses</span> <span word="significant">significant</span> <span word="memory">memory</span> <span word="as">as</span> <span word="well">well</span>.</p><p><span word="A">A</span> <span word="UNION">UNION</span> <span word="ALL">ALL</span> <span word="conversely">conversely</span> <span word="just">just</span> <span word="dumps">dumps</span> <span word="collection">collection</span> <span word="of">of</span> <span word="both">both</span> <span word="sets">sets</span> <span word="together">together</span> <span word="in">in</span> <span word="random">random</span> <span word="order">order</span>, <span word="not">not</span> <span word="worrying">worrying</span> <span word="about">about</span> <span word="duplicates">duplicates</span>.</p><p>&<span word="nbsp">nbsp</span>;</p><p>2. <span word="What">What</span> <span word="are">are</span> <span word="some">some</span> <span word="advantages">advantages</span> <span word="to">to</span> <span word="using">using</span> <span word="Oracle">Oracle</span>'<span word="s">s</span> <span word="CREATE">CREATE</span> <span word="DATABASE">DATABASE</span> <span word="statement">statement</span> <span word="to">to</span> <span word="create">create</span> <span word="a">a</span> <span word="new">new</span> <span word="database">database</span> <span word="manually">manually</span>?</p><p>&<span word="nbsp">nbsp</span>;</p><p>&<span word="bull">bull</span>; <span word="You">You</span> <span word="can">can</span> <span word="script">script</span> <span word="the">the</span> <span word="process">process</span> <span word="to">to</span> <span word="include">include</span> <span word="it">it</span> <span word="in">in</span> <span word="a">a</span> <span word="set">set</span> <span word="of">of</span> <span word="install">install</span> <span word="scripts">scripts</span> <span word="you">you</span> <span word="deliver">deliver</span> <span word="with">with</span> <span word="a">a</span> <span word="product">product</span>.</p><p>&<span word="bull">bull</span>; <span word="You">You</span> <span word="can">can</span> <span word="put">put</span> <span word="your">your</span> <span word="create">create</span> <span word="database">database</span> <span word="script">script</span> <span word="in">in</span> <span word="CVS">CVS</span> <span word="for">for</span> <span word="version">version</span> <span word="control">control</span>, <span word="so">so</span> <span word="as">as</span> <span word="you">you</span> <span word="make">make</span> <span word="changes">changes</span> <span word="or">or</span> <span word="adjustments">adjustments</span> <span word="to">to</span> <span word="it">it</span>, <span word="you">you</span> <span word="can">can</span> <span word="track">track</span> <span word="them">them</span> <span word="like">like</span> <span word="you">you</span> <span word="do">do</span> <span word="changes">changes</span> <span word="to">to</span> <span word="software">software</span> <span word="code">code</span>.</p><p>&<span word="bull">bull</span>; <span word="You">You</span> <span word="can">can</span> <span word="log">log</span> <span word="the">the</span> <span word="output">output</span> <span word="and">and</span> <span word="review">review</span> <span word="it">it</span> <span word="for">for</span> <span word="errors">errors</span>.</p><p>&<span word="bull">bull</span>; <span word="You">You</span> <span word="learn">learn</span> <span word="more">more</span> <span word="about">about</span> <span word="the">the</span> <span word="process">process</span> <span word="of">of</span> <span word="database">database</span> <span word="creation">creation</span>, <span word="such">such</span> <span word="as">as</span> <span word="what">what</span> <span word="options">options</span> <span word="are">are</span> <span word="available">available</span> <span word="and">and</span> <span word="why">why</span>.</p><p>&<span word="nbsp">nbsp</span>;</p><p>3. <span word="What">What</span> <span word="are">are</span> <span word="three">three</span> <span word="rules">rules</span> <span word="of">of</span> <span word="thumb">thumb</span> <span word="to">to</span> <span word="create">create</span> <span word="good">good</span> <span word="passwords">passwords</span>? <span word="How">How</span> <span word="would">would</span> <span word="a">a</span> <span word="DBA">DBA</span> <span word="enforce">enforce</span> <span word="those">those</span> <span word="rules">rules</span> <span word="in">in</span> <span word="Oracle">Oracle</span>? <span word="What">What</span> <span word="business">business</span> <span word="challenges">challenges</span> <span word="might">might</span> <span word="you">you</span> <span word="encounter">encounter</span>?</p>
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