mirror of https://github.com/apache/cassandra
updated documentation for CQL TRUNCATE
Patch by eevans for CASSANDRA-1716 git-svn-id: https://svn.apache.org/repos/asf/cassandra/trunk@1039596 13f79535-47bb-0310-9956-ffa450edef68
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Eric Evans
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<?xml version='1.0' encoding='utf-8' ?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/></head><body><h1 id="CassandraQueryLanguageCQLv0.99.1">Cassandra Query Language (CQL) v0.99.1</h1><h2 id="TableofContents">Table of Contents</h2><ol style="list-style: none;"><li><a href="#CassandraQueryLanguageCQLv0.99.1">Cassandra Query Language (CQL) v0.99.1</a><ol style="list-style: none;"><li><a href="#TableofContents">Table of Contents</a></li><li><a href="#USE">USE</a></li><li><a href="#SELECT">SELECT</a><ol style="list-style: none;"><li><a href="#SpecifyingColumns">Specifying Columns</a></li><li><a href="#ColumnFamily">Column Family</a></li><li><a href="#ConsistencyLevel">Consistency Level</a></li><li><a href="#Filteringrows">Filtering rows</a></li><li><a href="#Limits">Limits</a></li></ol></li><li><a href="#UPDATE">UPDATE</a><ol style="list-style: none;"><li><a href="#ColumnFamily2">Column Family</a></li><li><a href="#ConsistencyLevel2">Consistency Level</a></li><li><a href="#SpecifyingColumnsandRow">Specifying Columns and Row</a></li></ol></li><li><a href="#CommonIdioms">Common Idioms</a><ol style="list-style: none;"><li><a href="#consistency">Specifying Consistency</a></li><li><a href="#terms">Term specification</a><ol style="list-style: none;"><li><a href="#StringLiterals">String Literals</a></li><li><a href="#Integerslongs">Integers / longs</a></li></ol></li></ol></li></ol></li></ol><h2 id="USE">USE</h2><p><i>Synopsis:</i></p><pre><code>USE <KEYSPACE>;
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<?xml version='1.0' encoding='utf-8' ?><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/></head><body><h1 id="CassandraQueryLanguageCQLv0.99.1">Cassandra Query Language (CQL) v0.99.1</h1><h2 id="TableofContents">Table of Contents</h2><ol style="list-style: none;"><li><a href="#CassandraQueryLanguageCQLv0.99.1">Cassandra Query Language (CQL) v0.99.1</a><ol style="list-style: none;"><li><a href="#TableofContents">Table of Contents</a></li><li><a href="#USE">USE</a></li><li><a href="#SELECT">SELECT</a><ol style="list-style: none;"><li><a href="#SpecifyingColumns">Specifying Columns</a></li><li><a href="#ColumnFamily">Column Family</a></li><li><a href="#ConsistencyLevel">Consistency Level</a></li><li><a href="#Filteringrows">Filtering rows</a></li><li><a href="#Limits">Limits</a></li></ol></li><li><a href="#UPDATE">UPDATE</a><ol style="list-style: none;"><li><a href="#ColumnFamily2">Column Family</a></li><li><a href="#ConsistencyLevel2">Consistency Level</a></li><li><a href="#SpecifyingColumnsandRow">Specifying Columns and Row</a></li></ol></li><li><a href="#TRUNCATE">TRUNCATE</a></li><li><a href="#CommonIdioms">Common Idioms</a><ol style="list-style: none;"><li><a href="#consistency">Specifying Consistency</a></li><li><a href="#terms">Term specification</a><ol style="list-style: none;"><li><a href="#StringLiterals">String Literals</a></li><li><a href="#Integerslongs">Integers / longs</a></li></ol></li></ol></li></ol></li></ol><h2 id="USE">USE</h2><p><i>Synopsis:</i></p><pre><code>USE <KEYSPACE>;
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</code></pre><p>A <code>USE</code> statement consists of the <code>USE</code> keyword, followed by a valid keyspace name. Its purpose is to assign the per-connection, current working keyspace. All subsequent keyspace-specific actions will be performed in the context of the supplied value.</p><h2 id="SELECT">SELECT</h2><p><i>Synopsis:</i></p><pre><code>SELECT [FIRST N] [REVERSED] <SELECT EXPR> FROM <COLUMN FAMILY> [USING <CONSISTENCY>]
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[WHERE <CLAUSE>] [LIMIT N];
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</code></pre><p>A <code>SELECT</code> is used to read one or more records from a Cassandra column family. It returns a result-set of rows, where each row consists of a key and a collection of columns corresponding to the query.</p><h3 id="SpecifyingColumns">Specifying Columns</h3><pre><code>SELECT [FIRST N] [REVERSED] name1, name2, name3 FROM ...
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@ -18,5 +18,6 @@ UPDATE CF1 SET name1 = value1, name2 = value2 WHERE KEY = keyname1;
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UPDATE CF1 SET name3 = value3 WHERE KEY = keyname2;
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UPDATE CF2 SET name4 = value4, name5 = value5 WHERE KEY = keyname3;
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APPLY BATCH
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</code></pre><p>When batching UPDATEs, a single consistency level is used for the entire batch, it appears after the <code>BEGIN BATCH</code> statement, and uses the standard <a href="#consistency">consistency level specification</a>. Batch UPDATEs default to <code>CONSISTENCY.ONE</code> when left unspecified.</p><p><em>NOTE: While there are no isolation guarantees, <code>UPDATE</code> queries are atomic within a give record.</em></p><h2 id="CommonIdioms">Common Idioms</h2><h3 id="consistency">Specifying Consistency</h3><pre><code>... USING <CONSISTENCY> ...
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</code></pre><p>When batching UPDATEs, a single consistency level is used for the entire batch, it appears after the <code>BEGIN BATCH</code> statement, and uses the standard <a href="#consistency">consistency level specification</a>. Batch UPDATEs default to <code>CONSISTENCY.ONE</code> when left unspecified.</p><p><em>NOTE: While there are no isolation guarantees, <code>UPDATE</code> queries are atomic within a give record.</em></p><h2 id="TRUNCATE">TRUNCATE</h2><p><em>Synopsis:</em></p><pre><code>TRUNCATE <COLUMN FAMILY>
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</code></pre><p>Accepts a single argument for the column family name, and permanently removes all data from said column family.</p><h2 id="CommonIdioms">Common Idioms</h2><h3 id="consistency">Specifying Consistency</h3><pre><code>... USING <CONSISTENCY> ...
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</code></pre><p>Consistency level specifications are made up the keyword <code>USING</code>, followed by a consistency level identifier. Valid consistency levels are as follows:</p><ul><li><code>CONSISTENCY.ZERO</code></li><li><code>CONSISTENCY.ONE</code> (default)</li><li><code>CONSISTENCY.QUORUM</code></li><li><code>CONSISTENCY.ALL</code></li><li><code>CONSISTENCY.DCQUORUM</code></li><li><code>CONSISTENCY.DCQUORUMSYNC</code></li></ul><h3 id="terms">Term specification</h3><p>Where possible, the type of terms are inferred; the following term types are supported:</p><h4 id="StringLiterals">String Literals</h4><p>String literals are any value enclosed in double-quotes, (`"`). String literals are treated as raw bytes; no interpolation is performed.</p><h4 id="Integerslongs">Integers / longs</h4><p>Integers are any term consisting soley of unquoted numericals, longs are any otherwise valid integer term followed by an upper case “L”, (e.g. 100L). It is an error to specify an integer term that will not fit in 4 bytes unsigned, or a long that will not fit in 8 bytes unsigned.</p></body></html>
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@ -112,6 +112,15 @@ When batching UPDATEs, a single consistency level is used for the entire batch,
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_NOTE: While there are no isolation guarantees, @UPDATE@ queries are atomic within a give record._
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h2. TRUNCATE
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_Synopsis:_
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bc.
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TRUNCATE <COLUMN FAMILY>
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Accepts a single argument for the column family name, and permanently removes all data from said column family.
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h2. Common Idioms
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h3(#consistency). Specifying Consistency
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