shard-crystal-db/api/0.9.0/DB/Connection.html
2020-09-30 17:51:30 -03:00

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<title>DB::Connection - db 0.9.0</title>
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db
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0.9.0
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<li class=" " data-id="db/DB/Any" data-name="db::any">
<a href="../DB/Any.html">Any</a>
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<a href="../DB/BeginTransaction.html">BeginTransaction</a>
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<a href="../DB/Connection.html">Connection</a>
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<a href="../DB/Pool/TimeoutHelper.html">TimeoutHelper</a>
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<a href="../DB/PoolPreparedStatement.html">PoolPreparedStatement</a>
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<a href="../DB/PoolRetryAttemptsExceeded.html">PoolRetryAttemptsExceeded</a>
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<a href="../DB/Rollback.html">Rollback</a>
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<a href="../DB/SavePointTransaction.html">SavePointTransaction</a>
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<a href="../DB/Serializable.html">Serializable</a>
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<a href="../DB/Serializable/NonStrict.html">NonStrict</a>
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<a href="../DB/TopLevelTransaction.html">TopLevelTransaction</a>
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<a href="../DB/Transaction.html">Transaction</a>
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<div class="main-content">
<h1 class="type-name">
<span class="kind">abstract class</span> DB::Connection
</h1>
<ul class="superclass-hierarchy"><li class="superclass"><a href="../DB/Connection.html">DB::Connection</a></li><li class="superclass">Reference</li><li class="superclass">Object</li></ul>
<h2>
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Overview
</h2>
<p>Database driver implementors must subclass <code><a href="../DB/Connection.html">Connection</a></code>.</p>
<p>Represents one active connection to a database.</p>
<p>Users should never instantiate a <code><a href="../DB/Connection.html">Connection</a></code> manually. Use <code><a href="../DB.html#open(uri:URI%7CString)-class-method">DB#open</a></code> or <code>Database#connection</code>.</p>
<p>Refer to <code><a href="../DB/QueryMethods.html">QueryMethods</a></code> for documentation about querying the database through this connection.</p>
<h3><a id="note-to-implementors" class="anchor" href="#note-to-implementors">
<svg class="octicon-link" aria-hidden="true">
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</a>Note to implementors</h3>
<p>The connection must be initialized in <code>#initialize</code> and closed in <code>#do_close</code>.</p>
<p>Override <code>#build_prepared_statement</code> method in order to return a prepared <code><a href="../DB/Statement.html">Statement</a></code> to allow querying.
Override <code>#build_unprepared_statement</code> method in order to return a unprepared <code><a href="../DB/Statement.html">Statement</a></code> to allow querying.
See also <code><a href="../DB/Statement.html">Statement</a></code> to define how the statements are executed.</p>
<p>If at any give moment the connection is lost a DB::ConnectionLost should be raised. This will
allow the connection pool to try to reconnect or use another connection if available.</p>
<h2>
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Included Modules
</h2>
<ul class="other-types-list">
<li class="other-type"><a href="../DB/BeginTransaction.html">DB::BeginTransaction</a></li>
<li class="other-type"><a href="../DB/Disposable.html">DB::Disposable</a></li>
<li class="other-type"><a href="../DB/SessionMethods.html">DB::SessionMethods</a>(<a href="../DB/Connection.html">DB::Connection</a>, <a href="../DB/Statement.html">DB::Statement</a>)</li>
</ul>
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Defined in:
</h2>
<h2>
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Constructors
</h2>
<ul class="list-summary">
<li class="entry-summary">
<a href="#new(context:ConnectionContext)-class-method" class="signature"><strong>.new</strong>(context : ConnectionContext)</a>
</li>
</ul>
<h2>
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Instance Method Summary
</h2>
<ul class="list-summary">
<li class="entry-summary">
<a href="#begin_transaction:Transaction-instance-method" class="signature"><strong>#begin_transaction</strong> : Transaction</a>
<div class="summary"><p>Creates a transaction from the current context.</p></div>
</li>
<li class="entry-summary">
<a href="#prepared_statements?:Bool-instance-method" class="signature"><strong>#prepared_statements?</strong> : Bool</a>
<div class="summary"><p>Returns whether by default the statements should be prepared or not.</p></div>
</li>
<li class="entry-summary">
<a href="#release-instance-method" class="signature"><strong>#release</strong></a>
<div class="summary"><p>return this connection to the pool managed by the database.</p></div>
</li>
</ul>
<div class="methods-inherited">
<h3>Instance methods inherited from module <code><a href="../DB/BeginTransaction.html">DB::BeginTransaction</a></code></h3>
<a href="../DB/BeginTransaction.html#begin_transaction:Transaction-instance-method" class="tooltip">
<span>begin_transaction : Transaction</span>
begin_transaction</a>,
<a href="../DB/BeginTransaction.html#transaction(&)-instance-method" class="tooltip">
<span>transaction(&)</span>
transaction</a>
<h3>Instance methods inherited from module <code><a href="../DB/SessionMethods.html">DB::SessionMethods</a>(<a href="../DB/Connection.html">DB::Connection</a>, <a href="../DB/Statement.html">DB::Statement</a>)</code></h3>
<a href="../DB/SessionMethods.html#build(query):Stmt-instance-method" class="tooltip">
<span>build(query) : Stmt</span>
build</a>,
<a href="../DB/SessionMethods.html#build_unprepared_statement(query):Stmt-instance-method" class="tooltip">
<span>build_unprepared_statement(query) : Stmt</span>
build_unprepared_statement</a>,
<a href="../DB/SessionMethods.html#fetch_or_build_prepared_statement(query):Stmt-instance-method" class="tooltip">
<span>fetch_or_build_prepared_statement(query) : Stmt</span>
fetch_or_build_prepared_statement</a>,
<a href="../DB/SessionMethods.html#prepared(query)-instance-method" class="tooltip">
<span>prepared(query)<br/>prepared</span>
prepared</a>,
<a href="../DB/SessionMethods.html#prepared_statements?:Bool-instance-method" class="tooltip">
<span>prepared_statements? : Bool</span>
prepared_statements?</a>,
<a href="../DB/SessionMethods.html#unprepared(query)-instance-method" class="tooltip">
<span>unprepared(query)<br/>unprepared</span>
unprepared</a>
<h3>Instance methods inherited from module <code><a href="../DB/QueryMethods.html">DB::QueryMethods</a>(<a href="../DB/Statement.html">DB::Statement</a>)</code></h3>
<a href="../DB/QueryMethods.html#exec(query,*args_,args:Array?=nil)-instance-method" class="tooltip">
<span>exec(query, *args_, args : Array? = <span class="n">nil</span>)</span>
exec</a>,
<a href="../DB/QueryMethods.html#query(query,*args_,args:Array?=nil)-instance-method" class="tooltip">
<span>query(query, *args_, args : Array? = <span class="n">nil</span>)<br/>query(query, *args_, args : Array? = <span class="n">nil</span>, &)</span>
query</a>,
<a href="../DB/QueryMethods.html#query_all(query,*args_,args:Array?=nil,astype:Class)-instance-method" class="tooltip">
<span>query_all(query, *args_, args : Array? = <span class="n">nil</span>, as type : Class)<br/>query_all(query, *args_, args : Array? = <span class="n">nil</span>, as types : NamedTuple)<br/>query_all(query, *args_, args : Array? = <span class="n">nil</span>, &block : ResultSet -> U) : Array(U) forall U<br/>query_all(query, *args_, args : Array? = <span class="n">nil</span>, as types : Tuple)</span>
query_all</a>,
<a href="../DB/QueryMethods.html#query_each(query,*args_,args:Array?=nil,&)-instance-method" class="tooltip">
<span>query_each(query, *args_, args : Array? = <span class="n">nil</span>, &)</span>
query_each</a>,
<a href="../DB/QueryMethods.html#query_one(query,*args_,args:Array?=nil,&block:ResultSet-%3EU):UforallU-instance-method" class="tooltip">
<span>query_one(query, *args_, args : Array? = <span class="n">nil</span>, &block : ResultSet -> U) : U forall U<br/>query_one(query, *args_, args : Array? = <span class="n">nil</span>, as types : Tuple)<br/>query_one(query, *args_, args : Array? = <span class="n">nil</span>, as types : NamedTuple)<br/>query_one(query, *args_, args : Array? = <span class="n">nil</span>, as type : Class)</span>
query_one</a>,
<a href="../DB/QueryMethods.html#query_one?(query,*args_,args:Array?=nil,astype:Class)-instance-method" class="tooltip">
<span>query_one?(query, *args_, args : Array? = <span class="n">nil</span>, as type : Class)<br/>query_one?(query, *args_, args : Array? = <span class="n">nil</span>, as types : NamedTuple)<br/>query_one?(query, *args_, args : Array? = <span class="n">nil</span>, as types : Tuple)<br/>query_one?(query, *args_, args : Array? = <span class="n">nil</span>, &block : ResultSet -> U) : U? forall U</span>
query_one?</a>,
<a href="../DB/QueryMethods.html#scalar(query,*args_,args:Array?=nil)-instance-method" class="tooltip">
<span>scalar(query, *args_, args : Array? = <span class="n">nil</span>)</span>
scalar</a>
<h3>Instance methods inherited from module <code><a href="../DB/Disposable.html">DB::Disposable</a></code></h3>
<a href="../DB/Disposable.html#close-instance-method" class="tooltip">
<span>close</span>
close</a>,
<a href="../DB/Disposable.html#closed?-instance-method" class="tooltip">
<span>closed?</span>
closed?</a>
</div>
<h2>
<a id="constructor-detail" class="anchor" href="#constructor-detail">
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<use href="#octicon-link"/>
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Constructor Detail
</h2>
<div class="entry-detail" id="new(context:ConnectionContext)-class-method">
<div class="signature">
def self.<strong>new</strong>(context : <a href="../DB/ConnectionContext.html">ConnectionContext</a>)
<a class="method-permalink" href="#new(context:ConnectionContext)-class-method">#</a>
</div>
<br/>
<div>
</div>
</div>
<h2>
<a id="instance-method-detail" class="anchor" href="#instance-method-detail">
<svg class="octicon-link" aria-hidden="true">
<use href="#octicon-link"/>
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Instance Method Detail
</h2>
<div class="entry-detail" id="begin_transaction:Transaction-instance-method">
<div class="signature">
def <strong>begin_transaction</strong> : <a href="../DB/Transaction.html">Transaction</a>
<a class="method-permalink" href="#begin_transaction:Transaction-instance-method">#</a>
</div>
<div class="doc">
<div class="doc-inherited">
Description copied from module <a href="../DB/BeginTransaction.html">DB::BeginTransaction</a>
</div>
<p>Creates a transaction from the current context.
If is expected that either <code><a href="../DB/Transaction.html#commit-instance-method">Transaction#commit</a></code> or <code><a href="../DB/Transaction.html#rollback-instance-method">Transaction#rollback</a></code>
are called explicitly to release the context.</p>
</div>
<br/>
<div>
</div>
</div>
<div class="entry-detail" id="prepared_statements?:Bool-instance-method">
<div class="signature">
def <strong>prepared_statements?</strong> : Bool
<a class="method-permalink" href="#prepared_statements?:Bool-instance-method">#</a>
</div>
<div class="doc">
<div class="doc-inherited">
Description copied from module <a href="../DB/SessionMethods.html">DB::SessionMethods</a>(<a href="../DB/Connection.html">DB::Connection</a>, <a href="../DB/Statement.html">DB::Statement</a>)
</div>
<p>Returns whether by default the statements should
be prepared or not.</p>
</div>
<br/>
<div>
</div>
</div>
<div class="entry-detail" id="release-instance-method">
<div class="signature">
def <strong>release</strong>
<a class="method-permalink" href="#release-instance-method">#</a>
</div>
<div class="doc">
<p>return this connection to the pool
managed by the database. Should be used
only if the connection was obtained by <code><a href="../DB/Database.html#checkout-instance-method">Database#checkout</a></code>.</p>
</div>
<br/>
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