shard-crystal-db/api/0.10.1/DB/Database.html
2021-03-22 17:20:51 -03:00

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db
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<div class="main-content">
<h1 class="type-name">
<span class="kind">class</span> DB::Database
</h1>
<ul class="superclass-hierarchy"><li class="superclass"><a href="../DB/Database.html">DB::Database</a></li><li class="superclass">Reference</li><li class="superclass">Object</li></ul>
<h2>
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Overview
</h2>
<p>Acts as an entry point for database access.
Connections are managed by a pool.
Use <code><a href="../DB.html#open(uri:URI%7CString)-class-method">DB#open</a></code> to create a <code><a href="../DB/Database.html">Database</a></code> instance.</p>
<p>Refer to <code><a href="../DB/QueryMethods.html">QueryMethods</a></code> and <code><a href="../DB/SessionMethods.html">SessionMethods</a></code> for documentation about querying the database.</p>
<h2><a id="database-uri" class="anchor" href="#database-uri">
<svg class="octicon-link" aria-hidden="true">
<use href="#octicon-link"/>
</svg>
</a>Database URI</h2>
<p>Connection parameters are configured in a URI. The format is specified by the individual
database drivers. See the <a href="https://crystal-lang.org/reference/database/">reference book</a> for examples.</p>
<p>The connection pool can be configured from URI parameters:</p>
<ul><li><code>initial_pool_size</code> (default 1)</li><li><code>max_pool_size</code> (default 0 = unlimited)</li><li><code>max_idle_pool_size</code> (default 1)</li><li><code>checkout_timeout</code> (default 5.0)</li><li><code>retry_attempts</code> (default 1)</li><li><code>retry_delay</code> (in seconds, default 1.0)</li></ul></ul>
<p>When querying a database, prepared statements are used by default.
This can be changed from the <code>prepared_statements</code> URI parameter:</p>
<ul><li><code>prepared_statements</code> (true, or false, default true)</li></ul></ul>
<h2>
<a id="included-modules" class="anchor" href="#included-modules">
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Included Modules
</h2>
<ul class="other-types-list">
<li class="other-type"><a href="../DB/ConnectionContext.html">DB::ConnectionContext</a></li>
<li class="other-type"><a href="../DB/SessionMethods.html">DB::SessionMethods</a>(<a href="../DB/Database.html">DB::Database</a>, <a href="../DB/PoolStatement.html">DB::PoolStatement</a>)</li>
</ul>
<h2>
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Defined in:
</h2>
<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L30" target="_blank">
db/database.cr
</a>
<br/>
<h2>
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Instance Method Summary
</h2>
<ul class="list-summary">
<li class="entry-summary">
<a href="#checkout-instance-method" class="signature"><strong>#checkout</strong></a>
<div class="summary"><p>returns a connection from the pool the returned connection must be returned to the pool by explictly calling <code><a href="../DB/Connection.html#release-instance-method">Connection#release</a></code></p></div>
</li>
<li class="entry-summary">
<a href="#close-instance-method" class="signature"><strong>#close</strong></a>
<div class="summary"><p>Closes all connection to the database.</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>Return whether the statements should be prepared by default</p></div>
</li>
<li class="entry-summary">
<a href="#setup_connection(&proc:Connection-%3ENil)-instance-method" class="signature"><strong>#setup_connection</strong>(&proc : Connection -> Nil)</a>
<div class="summary"><p>Run the specified block every time a new connection is established, yielding the new connection to the block.</p></div>
</li>
<li class="entry-summary">
<a href="#transaction(&)-instance-method" class="signature"><strong>#transaction</strong>(&)</a>
<div class="summary"><p>yields a <code><a href="../DB/Transaction.html">Transaction</a></code> from a connection of the pool Refer to <code><a href="../DB/BeginTransaction.html#transaction(&)-instance-method">BeginTransaction#transaction</a></code> for documentation.</p></div>
</li>
<li class="entry-summary">
<a href="#uri:URI-instance-method" class="signature"><strong>#uri</strong> : URI</a>
<div class="summary"><p>Returns the uri with the connection settings to the database</p></div>
</li>
<li class="entry-summary">
<a href="#using_connection(&)-instance-method" class="signature"><strong>#using_connection</strong>(&)</a>
<div class="summary"><p>yields a connection from the pool the connection is returned to the pool when the block ends</p></div>
</li>
</ul>
<div class="methods-inherited">
<h3>Instance methods inherited from module <code><a href="../DB/ConnectionContext.html">DB::ConnectionContext</a></code></h3>
<a href="../DB/ConnectionContext.html#discard(connection:Connection)-instance-method" class="tooltip">
<span>discard(connection : Connection)</span>
discard</a>,
<a href="../DB/ConnectionContext.html#prepared_statements?:Bool-instance-method" class="tooltip">
<span>prepared_statements? : Bool</span>
prepared_statements?</a>,
<a href="../DB/ConnectionContext.html#release(connection:Connection)-instance-method" class="tooltip">
<span>release(connection : Connection)</span>
release</a>,
<a href="../DB/ConnectionContext.html#uri:URI-instance-method" class="tooltip">
<span>uri : URI</span>
uri</a>
<h3>Instance methods inherited from module <code><a href="../DB/SessionMethods.html">DB::SessionMethods</a>(<a href="../DB/Database.html">DB::Database</a>, <a href="../DB/PoolStatement.html">DB::PoolStatement</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/PoolStatement.html">DB::PoolStatement</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>
</div>
<h2>
<a id="instance-method-detail" class="anchor" href="#instance-method-detail">
<svg class="octicon-link" aria-hidden="true">
<use href="#octicon-link"/>
</svg>
</a>
Instance Method Detail
</h2>
<div class="entry-detail" id="checkout-instance-method">
<div class="signature">
def <strong>checkout</strong>
<a class="method-permalink" href="#checkout-instance-method">#</a>
</div>
<div class="doc">
<p>returns a connection from the pool
the returned connection must be returned
to the pool by explictly calling <code><a href="../DB/Connection.html#release-instance-method">Connection#release</a></code></p>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L133" target="_blank">View source</a>]
</div>
</div>
<div class="entry-detail" id="close-instance-method">
<div class="signature">
def <strong>close</strong>
<a class="method-permalink" href="#close-instance-method">#</a>
</div>
<div class="doc">
<p>Closes all connection to the database.</p>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L81" target="_blank">View source</a>]
</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/ConnectionContext.html">DB::ConnectionContext</a>
</div>
<p>Return whether the statements should be prepared by default</p>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L42" target="_blank">View source</a>]
</div>
</div>
<div class="entry-detail" id="setup_connection(&proc:Connection->Nil)-instance-method">
<div class="signature">
def <strong>setup_connection</strong>(&proc : <a href="../DB/Connection.html">Connection</a> -> Nil)
<a class="method-permalink" href="#setup_connection(&proc:Connection-%3ENil)-instance-method">#</a>
</div>
<div class="doc">
<p>Run the specified block every time a new connection is established, yielding the new connection
to the block.</p>
<pre><code class="language-crystal">db <span class="o">=</span> <span class="t">DB</span>.open(<span class="t">DB_URL</span>)
db.setup_connection <span class="k">do</span> <span class="o">|</span>connection<span class="o">|</span>
connection.exec <span class="s">&quot;SET TIME ZONE &#39;America/New_York&#39;&quot;</span>
<span class="k">end</span></code></pre>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L73" target="_blank">View source</a>]
</div>
</div>
<div class="entry-detail" id="transaction(&)-instance-method">
<div class="signature">
def <strong>transaction</strong>(&)
<a class="method-permalink" href="#transaction(&)-instance-method">#</a>
</div>
<div class="doc">
<p>yields a <code><a href="../DB/Transaction.html">Transaction</a></code> from a connection of the pool
Refer to <code><a href="../DB/BeginTransaction.html#transaction(&)-instance-method">BeginTransaction#transaction</a></code> for documentation.</p>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L141" target="_blank">View source</a>]
</div>
</div>
<div class="entry-detail" id="uri:URI-instance-method">
<div class="signature">
def <strong>uri</strong> : URI
<a class="method-permalink" href="#uri:URI-instance-method">#</a>
</div>
<div class="doc">
<p>Returns the uri with the connection settings to the database</p>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L40" target="_blank">View source</a>]
</div>
</div>
<div class="entry-detail" id="using_connection(&)-instance-method">
<div class="signature">
def <strong>using_connection</strong>(&)
<a class="method-permalink" href="#using_connection(&)-instance-method">#</a>
</div>
<div class="doc">
<p>yields a connection from the pool
the connection is returned to the pool
when the block ends</p>
</div>
<br/>
<div>
[<a href="https://github.com/crystal-lang/crystal-db/blob/v0.10.1/src/db/database.cr#L121" target="_blank">View source</a>]
</div>
</div>
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