Author: slebresne Date: Mon Mar 10 17:03:32 2014 New Revision: 1576002 URL: http://svn.apache.org/r1576002 Log: Update CQL doc
Modified: cassandra/site/publish/doc/cql3/CQL-1.2.html cassandra/site/publish/doc/cql3/CQL-2.0.html Modified: cassandra/site/publish/doc/cql3/CQL-1.2.html URL: http://svn.apache.org/viewvc/cassandra/site/publish/doc/cql3/CQL-1.2.html?rev=1576002&r1=1576001&r2=1576002&view=diff ============================================================================== --- cassandra/site/publish/doc/cql3/CQL-1.2.html (original) +++ cassandra/site/publish/doc/cql3/CQL-1.2.html Mon Mar 10 17:03:32 2014 @@ -59,9 +59,6 @@ CREATE KEYSPACE Excalibur <column-definition> ::= <identifier> <type> ( PRIMARY KEY )? | PRIMARY KEY '(' <partition-key> ( ',' <identifier> )* ')' -<partition-key> ::= <partition-key> - | '(' <partition-key> ( ',' <identifier> )* ')' - <partition-key> ::= <identifier> | '(' <identifier> (',' <identifier> )* ')' @@ -93,7 +90,7 @@ CREATE TABLE timeline ( other text, PRIMARY KEY (k) ) -</pre></pre><p>Moreover, a table must define at least one column that is not part of the PRIMARY KEY as a row exists in Cassandra only if it contains at least one value for one such column.</p><h4 id="createTablepartitionClustering">Partition key and clustering columns</h4><p>In CQL, the order in which columns are defined for the <code>PRIMARY KEY</code> matters. The first column of the key is called the <i>partition key</i>. It has the property that all the rows sharing the same partition key (even across table in fact) are stored on the same physical node. Also, insertion/update/deletion on rows sharing the same partition key for a given table are performed <i>atomically</i> and in <i>isolation</i>. Note that it is possible to have a composite partition key, i.e. a partition key formed of multiple columns, using an extra set of parentheses to define which columns forms the partition key.</p><p>The remaining columns of the <code>PRIMARY KEY</code> definition, if any, are called __c lustering columns. On a given physical node, rows for a given partition key are stored in the order induced by the clustering columns, making the retrieval of rows in that clustering order particularly efficient (see <a href="#selectStmt"><tt>SELECT</tt></a>).</p><h4 id="createTableOptions"><code><option></code></h4><p>The <code>CREATE TABLE</code> statement supports a number of options that controls the configuration of a new table. These options can be specified after the <code>WITH</code> keyword.</p><p>The first of these option is <code>COMPACT STORAGE</code>. This option is mainly targeted towards backward compatibility for definitions created before CQL3 (see <a href="http://www.datastax.com/dev/blog/thrift-to-cql3">www.datastax.com/dev/blog/thrift-to-cql3</a> for more details). The option also provides a slightly more compact layout of data on disk but at the price of diminished flexibility and extensibility for the table. Most notably, <code>COMPACT STORAGE</code> table s cannot have collections and a <code>COMPACT STORAGE</code> table with at least one clustering column supports exactly one (as in not 0 nor more than 1) column not part of the <code>PRIMARY KEY</code> definition (which imply in particular that you cannot add nor remove columns after creation). For those reasons, <code>COMPACT STORAGE</code> is not recommended outside of the backward compatibility reason evoked above.</p><p>Another option is <code>CLUSTERING ORDER</code>. It allows to define the ordering of rows on disk. It takes the list of the clustering column names with, for each of them, the on-disk order (Ascending or descending). Note that this option affects <a href="#selectOrderBy">what <code>ORDER BY</code> are allowed during <code>SELECT</code></a>.</p><p>Table creation supports the following other <code><property></code>:</p><table><tr><th>option </th><th>kind </th><th>default </th><th>description</th></tr><tr><td><code>comment</code> </td><td><em>simple</em> </td><td>none </td><td>A free-form, human-readable comment.</td></tr><tr><td><code>read_repair_chance</code> </td><td><em>simple</em> </td><td>0.1 </td><td>The probability with which to query extra nodes (e.g. more nodes than required by the consistency level) for the purpose of read repairs.</td></tr><tr><td><code>dclocal_read_repair_chance</code> </td><td><em>simple</em> </td><td>0 </td><td>The probability with which to query extra nodes (e.g. more nodes than required by the consistency level) belonging to the same data center than the read coordinator for the purpose of read repairs.</td></tr><tr><td><code>gc_grace_seconds</code> </td><td><em>simple</em> </td><td>864000 </td><td>Time to wait before garbage collecting tombstones (deletion markers).</td></tr><tr><td><code>bloom_filter_fp_chance</code> </td><td><em>simple</em> </td><td>0.00075 </td><td>The target probability of false positive o f the sstable bloom filters. Said bloom filters will be sized to provide the provided probability (thus lowering this value impact the size of bloom filters in-memory and on-disk)</td></tr><tr><td><code>compaction</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>The compaction otpions to use, see below.</td></tr><tr><td><code>compression</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>Compression options, see below. </td></tr><tr><td><code>replicate_on_write</code> </td><td><em>simple</em> </td><td>true </td><td>Whether to replicate data on write. This can only be set to false for tables with counters values. Disabling this is dangerous and can result in random lose of counters, don’t disable unless you are sure to know what you are doing</td></tr><tr><td><code>caching</code> </td><td><em>simple</em> </td><td>keys_only </td><td>Whether to cache keys (“key cacheR 21;) and/or rows (“row cache”) for this table. Valid values are: <code>all</code>, <code>keys_only</code>, <code>rows_only</code> and <code>none</code>. </td></tr></table><h4 id="compactionOptions"><code>compaction</code> options</h4><p>The <code>compaction</code> property must at least define the <code>'class'</code> sub-option, that defines the compaction strategy class to use. The default supported class are <code>'SizeTieredCompactionStrategy'</code> and <code>'LeveledCompactionStrategy'</code>. Custom strategy can be provided by specifying the full class name as a <a href="#constants">string constant</a>. The rest of the sub-options depends on the chosen class. The sub-options supported by the default classes are:</p><table><tr><th>option </th><th>supported compaction strategy </th><th>default </th><th>description </th></tr><tr><td><code>tombstone_threshold</code> </td><td><em>all</em> </td><td>0.2 </t d><td>A ratio such that if a sstable has more than this ratio of gcable tombstones over all contained columns, the sstable will be compacted (with no other sstables) for the purpose of purging those tombstones. </td></tr><tr><td><code>tombstone_compaction_interval</code> </td><td><em>all</em> </td><td>1 day </td><td>The mininum time to wait after an sstable creation time before considering it for “tombstone compaction”, where “tombstone compaction” is the compaction triggered if the sstable has more gcable tombstones than <code>tombstone_threshold</code>. </td></tr><tr><td><code>min_sstable_size</code> </td><td>SizeTieredCompactionStrategy </td><td>50MB </td><td>The size tiered strategy groups SSTables to compact in buckets. A bucket groups SSTables that differs from less than 50% in size. However, for small sizes, this would result in a bucketing that is too fine grained. <code>min_sstable_size</code> defin es a size threshold (in bytes) below which all SSTables belong to one unique bucket</td></tr><tr><td><code>min_threshold</code> </td><td>SizeTieredCompactionStrategy </td><td>4 </td><td>Minimum number of SSTables needed to start a minor compaction.</td></tr><tr><td><code>max_threshold</code> </td><td>SizeTieredCompactionStrategy </td><td>32 </td><td>Maximum number of SSTables processed by one minor compaction.</td></tr><tr><td><code>bucket_low</code> </td><td>SizeTieredCompactionStrategy </td><td>0.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose sizes diverges by at most 50%)</td></tr><tr><td><code>bucket_high</code> </td><td>SizeTieredCompactionStrategy </td><td>1.5 </td><td>Size tiered consider sstables to be w ithin the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose sizes diverges by at most 50%).</td></tr><tr><td><code>sstable_size_in_mb</code> </td><td>LeveledCompactionStrategy </td><td>5MB </td><td>The target size (in MB) for sstables in the leveled strategy. Note that while sstable sizes should stay less or equal to <code>sstable_size_in_mb</code>, it is possible to exceptionally have a larger sstable as during compaction, data for a given partition key are never split into 2 sstables</td></tr></table><p>For the <code>compression</code> property, the following default sub-options are available:</p><table><tr><th>option </th><th>default </th><th>description </th></tr><tr><td><code>sstable_compression</code> </td><td>SnappyCompressor </td><td>The compression algorithm to use. Default compressor are: SnappyCompressor and DeflateCompresso r. Use an empty string (<code>''</code>) to disable compression. Custom compressor can be provided by specifying the full class name as a <a href="#constants">string constant</a>.</td></tr><tr><td><code>chunk_length_kb</code> </td><td>64KB </td><td>On disk SSTables are compressed by block (to allow random reads). This defines the size (in KB) of said block. Bigger values may improve the compression rate, but increases the minimum size of data to be read from disk for a read </td></tr><tr><td><code>crc_check_chance</code> </td><td>1.0 </td><td>When compression is enabled, each compressed block includes a checksum of that block for the purpose of detecting disk bitrot and avoiding the propagation of corruption to other replica. This option defines the probability with which those checksums are checked during read. By default they are always checked. Set to 0 to disable checksum checking and to 0.5 for instance to check them every other read</td></tr></t able><h4 id="Otherconsiderations">Other considerations:</h4><ul><li>When <a href="#insertStmt/"updating":#updateStmt">inserting</a> a given row, not all columns needs to be defined (except for those part of the key), and missing columns occupy no space on disk. Furthermore, adding new columns (see <a href=#alterStmt><tt>ALTER TABLE</tt></a>) is a constant time operation. There is thus no need to try to anticipate future usage (or to cry when you haven’t) when creating a table.</li></ul><h3 id="alterTableStmt">ALTER TABLE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><alter-table-stmt> ::= ALTER (TABLE | COLUMNFAMILY) <tablename> <instruction> +</pre></pre><h4 id="createTablepartitionClustering">Partition key and clustering columns</h4><p>In CQL, the order in which columns are defined for the <code>PRIMARY KEY</code> matters. The first column of the key is called the <i>partition key</i>. It has the property that all the rows sharing the same partition key (even across table in fact) are stored on the same physical node. Also, insertion/update/deletion on rows sharing the same partition key for a given table are performed <i>atomically</i> and in <i>isolation</i>. Note that it is possible to have a composite partition key, i.e. a partition key formed of multiple columns, using an extra set of parentheses to define which columns forms the partition key.</p><p>The remaining columns of the <code>PRIMARY KEY</code> definition, if any, are called __clustering columns. On a given physical node, rows for a given partition key are stored in the order induced by the clustering columns, making the retrieval of rows in that clusterin g order particularly efficient (see <a href="#selectStmt"><tt>SELECT</tt></a>).</p><h4 id="createTableOptions"><code><option></code></h4><p>The <code>CREATE TABLE</code> statement supports a number of options that controls the configuration of a new table. These options can be specified after the <code>WITH</code> keyword.</p><p>The first of these option is <code>COMPACT STORAGE</code>. This option is mainly targeted towards backward compatibility for definitions created before CQL3 (see <a href="http://www.datastax.com/dev/blog/thrift-to-cql3">www.datastax.com/dev/blog/thrift-to-cql3</a> for more details). The option also provides a slightly more compact layout of data on disk but at the price of diminished flexibility and extensibility for the table. Most notably, <code>COMPACT STORAGE</code> tables cannot have collections and a <code>COMPACT STORAGE</code> table with at least one clustering column supports exactly one (as in not 0 nor more than 1) column not part of the <cod e>PRIMARY KEY</code> definition (which imply in particular that you cannot add nor remove columns after creation). For those reasons, <code>COMPACT STORAGE</code> is not recommended outside of the backward compatibility reason evoked above.</p><p>Another option is <code>CLUSTERING ORDER</code>. It allows to define the ordering of rows on disk. It takes the list of the clustering column names with, for each of them, the on-disk order (Ascending or descending). Note that this option affects <a href="#selectOrderBy">what <code>ORDER BY</code> are allowed during <code>SELECT</code></a>.</p><p>Table creation supports the following other <code><property></code>:</p><table><tr><th>option </th><th>kind </th><th>default </th><th>description</th></tr><tr><td><code>comment</code> </td><td><em>simple</em> </td><td>none </td><td>A free-form, human-readable comment.</td></tr><tr><td><code>read_repair_chance</code> </td><td><em>simple</em > </td><td>0.1 </td><td>The probability with which to query extra > nodes (e.g. more nodes than required by the consistency level) for the > purpose of read > repairs.</td></tr><tr><td><code>dclocal_read_repair_chance</code> > </td><td><em>simple</em> </td><td>0 </td><td>The probability with > which to query extra nodes (e.g. more nodes than required by the consistency > level) belonging to the same data center than the read coordinator for the > purpose of read repairs.</td></tr><tr><td><code>gc_grace_seconds</code> > </td><td><em>simple</em> </td><td>864000 </td><td>Time to wait > before garbage collecting tombstones (deletion > markers).</td></tr><tr><td><code>bloom_filter_fp_chance</code> > </td><td><em>simple</em> </td><td>0.00075 </td><td>The target > probability of false positive of the sstable bloom filters. Said bloom > filters will be sized to provide the provided probability (thus lowering > this value impact the size of bloom filters in-memory and on-disk)</ td></tr><tr><td><code>compaction</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>The compaction otpions to use, see below.</td></tr><tr><td><code>compression</code> </td><td><em>map</em> </td><td><em>see below</em> </td><td>Compression options, see below. </td></tr><tr><td><code>replicate_on_write</code> </td><td><em>simple</em> </td><td>true </td><td>Whether to replicate data on write. This can only be set to false for tables with counters values. Disabling this is dangerous and can result in random lose of counters, don’t disable unless you are sure to know what you are doing</td></tr><tr><td><code>caching</code> </td><td><em>simple</em> </td><td>keys_only </td><td>Whether to cache keys (“key cache”) and/or rows (“row cache”) for this table. Valid values are: <code>all</code>, <code>keys_only</code>, <code>rows_only</code> and <code>none</code>. </td></tr></tabl e><h4 id="compactionOptions"><code>compaction</code> options</h4><p>The <code>compaction</code> property must at least define the <code>'class'</code> sub-option, that defines the compaction strategy class to use. The default supported class are <code>'SizeTieredCompactionStrategy'</code> and <code>'LeveledCompactionStrategy'</code>. Custom strategy can be provided by specifying the full class name as a <a href="#constants">string constant</a>. The rest of the sub-options depends on the chosen class. The sub-options supported by the default classes are:</p><table><tr><th>option </th><th>supported compaction strategy </th><th>default </th><th>description </th></tr><tr><td><code>tombstone_threshold</code> </td><td><em>all</em> </td><td>0.2 </td><td>A ratio such that if a sstable has more than this ratio of gcable tombstones over all contained columns, the sstable will be compacted (with no other sstables) for the purpose of purging those tombstones. </td></tr><tr><td><code>tombstone_compaction_interval</code> </td><td><em>all</em> </td><td>1 day </td><td>The mininum time to wait after an sstable creation time before considering it for “tombstone compaction”, where “tombstone compaction” is the compaction triggered if the sstable has more gcable tombstones than <code>tombstone_threshold</code>. </td></tr><tr><td><code>min_sstable_size</code> </td><td>SizeTieredCompactionStrategy </td><td>50MB </td><td>The size tiered strategy groups SSTables to compact in buckets. A bucket groups SSTables that differs from less than 50% in size. However, for small sizes, this would result in a bucketing that is too fine grained. <code>min_sstable_size</code> defines a size threshold (in bytes) below which all SSTables belong to one unique bucket</td></tr><tr><td><code>min_threshold</code> </td><td>SizeTieredCompactionStrategy </td><td>4 </td><td>Minimum number of SSTables needed to start a minor compaction.</td></tr><tr><td><code>max_threshold</code> </td><td>SizeTieredCompactionStrategy </td><td>32 </td><td>Maximum number of SSTables processed by one minor compaction.</td></tr><tr><td><code>bucket_low</code> </td><td>SizeTieredCompactionStrategy </td><td>0.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose sizes diverges by at most 50%)</td></tr><tr><td><code>bucket_high</code> </td><td>SizeTieredCompactionStrategy </td><td>1.5 </td><td>Size tiered consider sstables to be within the same bucket if their size is within [average_size * <code>bucket_low</code>, average_size * <code>bucket_high</code> ] (i.e the default groups sstable whose sizes diverges by at most 50%).</td></tr><tr><td><code>sstable_size_in_mb</code> </td><td>LeveledCompactionStrategy </td><td>5MB </td><td>The target size (in MB) for sstables in the leveled strategy. Note that while sstable sizes should stay less or equal to <code>sstable_size_in_mb</code>, it is possible to exceptionally have a larger sstable as during compaction, data for a given partition key are never split into 2 sstables</td></tr></table><p>For the <code>compression</code> property, the following default sub-options are available:</p><table><tr><th>option </th><th>default </th><th>description </th></tr><tr><td><code>sstable_compression</code> </td><td>SnappyCompressor </td><td>The compression algorithm to use. Default compressor are: SnappyCompressor and DeflateCompressor. Use an empty string (<code>''</code>) to disable compression. Custom compressor can be provided by specifying the full class name as a <a href="#constants">string constant</a>.</ td></tr><tr><td><code>chunk_length_kb</code> </td><td>64KB </td><td>On disk SSTables are compressed by block (to allow random reads). This defines the size (in KB) of said block. Bigger values may improve the compression rate, but increases the minimum size of data to be read from disk for a read </td></tr><tr><td><code>crc_check_chance</code> </td><td>1.0 </td><td>When compression is enabled, each compressed block includes a checksum of that block for the purpose of detecting disk bitrot and avoiding the propagation of corruption to other replica. This option defines the probability with which those checksums are checked during read. By default they are always checked. Set to 0 to disable checksum checking and to 0.5 for instance to check them every other read</td></tr></table><h4 id="Otherconsiderations">Other considerations:</h4><ul><li>When <a href="#insertStmt/"updating":#updateStmt">inserting</a> a given row, not all columns needs to b e defined (except for those part of the key), and missing columns occupy no space on disk. Furthermore, adding new columns (see <a href=#alterStmt><tt>ALTER TABLE</tt></a>) is a constant time operation. There is thus no need to try to anticipate future usage (or to cry when you haven’t) when creating a table.</li></ul><h3 id="alterTableStmt">ALTER TABLE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><alter-table-stmt> ::= ALTER (TABLE | COLUMNFAMILY) <tablename> <instruction> <instruction> ::= ALTER <identifier> TYPE <type> | ADD <identifier> <type> @@ -131,7 +128,7 @@ CREATE CUSTOM INDEX ON users (email) USI </pre></pre><p><br/><i>Sample:</i></p><pre class="sample"><pre>INSERT INTO NerdMovies (movie, director, main_actor, year) VALUES ('Serenity', 'Joss Whedon', 'Nathan Fillion', 2005) USING TTL 86400; -</pre></pre><p>The <code>INSERT</code> statement writes one or more columns for a given row in a table. Note that since a row is identified by its <code>PRIMARY KEY</code>, the columns that compose it must be specified. Also, since a row only exists when it contains one value for a column not part of the <code>PRIMARY KEY</code>, one such value must be specified too.</p><p>Note that unlike in SQL, <code>INSERT</code> does not check the prior existence of the row: the row is created if none existed before, and updated otherwise. Furthermore, there is no mean to know which of creation or update happened. In fact, the semantic of <code>INSERT</code> and <code>UPDATE</code> are identical.</p><p>All updates for an <code>INSERT</code> are applied atomically and in isolation.</p><p>Please refer to the <a href="#updateOptions"><code>UPDATE</code></a> section for information on the <code><option></code> available and to the <a href="#collections">collections</a> section for use of <code>& lt;collection-literal></code>. Also note that <code>INSERT</code> does not support counters, while <code>UPDATE</code> does.</p><h3 id="updateStmt">UPDATE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><update-stmt> ::= UPDATE <tablename> +</pre></pre><p>The <code>INSERT</code> statement writes one or more columns for a given row in a table. Note that since a row is identified by its <code>PRIMARY KEY</code>, at least the columns composing it must be specified.</p><p>Note that unlike in SQL, <code>INSERT</code> does not check the prior existence of the row: the row is created if none existed before, and updated otherwise. Furthermore, there is no mean to know which of creation or update happened. In fact, the semantic of <code>INSERT</code> and <code>UPDATE</code> are identical.</p><p>All updates for an <code>INSERT</code> are applied atomically and in isolation.</p><p>Please refer to the <a href="#updateOptions"><code>UPDATE</code></a> section for information on the <code><option></code> available and to the <a href="#collections">collections</a> section for use of <code><collection-literal></code>. Also note that <code>INSERT</code> does not support counters, while <code>UPDATE</code> does.</p><h3 id="updateSt mt">UPDATE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><update-stmt> ::= UPDATE <tablename> ( USING <option> ( AND <option> )* )? SET <assignment> ( ',' <assignment> )* WHERE <where-clause> @@ -155,7 +152,7 @@ SET director = 'Joss Whedon', WHERE movie = 'Serenity'; UPDATE UserActions SET total = total + 2 WHERE user = B70DE1D0-9908-4AE3-BE34-5573E5B09F14 AND action = 'click'; -</pre></pre><p><br/>The <code>UPDATE</code> statement writes one or more columns for a given row in a table. The <code><where-clause></code> is used to select the row to update and must include all columns composing the <code>PRIMARY KEY</code> (the <code>IN</code> relation is only supported for the last column of the partition key). Other columns values are specified through <code><assignment></code> after the <code>SET</code> keyword.</p><p>Note that unlike in SQL, <code>UPDATE</code> does not check the prior existence of the row: the row is created if none existed before, and updated otherwise. Furthermore, there is no mean to know which of creation or update happened. In fact, the semantic of <code>INSERT</code> and <code>UPDATE</code> are identical.</p><p>In an <code>UPDATE</code> statement, all updates within the same partition key are applied atomically and in isolation.</p><p>The <code>c = c + 3</code> form of <code><assignment></code> is used to increment/decrement counters. The identifier after the ‘=’ sign <strong>must</strong> be the same than the one before the ‘=’ sign (Only increment/decrement is supported on counters, not the assignment of a specific value).</p><p>The <code>id = id + <collection-literal></code> and <code>id[value1] = value2</code> forms of <code><assignment></code> are for collections. Please refer to the <a href="#collections">relevant section</a> for more details.</p><h4 id="updateOptions"><code><options></code></h4><p>The <code>UPDATE</code> and <code>INSERT</code> statements allows to specify the following options for the insertion:</p><ul><li><code>TIMESTAMP</code>: sets the timestamp for the operation. If not specified, the current time of the insertion (in microseconds) is used. This is usually a suitable default.</li><li><code>TTL</code>: allows to specify an optional Time To Live (in seconds) for the inserted values. If set, the inserted values are automatically removed from th e database after the specified time. Note that the TTL concerns the inserted values, not the column themselves. This means that any subsequent update of the column will also reset the TTL (to whatever TTL is specified in that update). By default, values never expire.</li></ul><h3 id="deleteStmt">DELETE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><delete-stmt> ::= DELETE ( <selection> ( ',' <selection> )* )? +</pre></pre><p><br/>The <code>UPDATE</code> statement writes one or more columns for a given row in a table. The <code><where-clause></code> is used to select the row to update and must include all columns composing the <code>PRIMARY KEY</code> (the <code>IN</code> relation is only supported for the last column of the partition key). Other columns values are specified through <code><assignment></code> after the <code>SET</code> keyword.</p><p>Note that unlike in SQL, <code>UPDATE</code> does not check the prior existence of the row: the row is created if none existed before, and updated otherwise. Furthermore, there is no mean to know which of creation or update happened. In fact, the semantic of <code>INSERT</code> and <code>UPDATE</code> are identical.</p><p>In an <code>UPDATE</code> statement, all updates within the same partition key are applied atomically and in isolation.</p><p>The <code>c = c + 3</code> form of <code><assignment></code> is used to increment/decrement counters. The identifier after the ‘=’ sign <strong>must</strong> be the same than the one before the ‘=’ sign (Only increment/decrement is supported on counters, not the assignment of a specific value).</p><p>The <code>id = id + <collection-literal></code> and <code>id[value1] = value2</code> forms of <code><assignment></code> are for collections. Please refer to the <a href="#collections">relevant section</a> for more details.</p><h4 id="updateOptions"><code><options></code></h4><p>The <code>UPDATE</code> and <code>INSERT</code> statements allows to specify the following options for the insertion:</p><ul><li><code>TIMESTAMP</code>: sets the timestamp for the operation. If not specified, the current time of the insertion (in microseconds) is used. This is usually a suitable default.</li><li><code>TTL</code>: allows to specify an optional Time To Live (in seconds) for the inserted values. If set, the inserted values are automatically removed from th e database after the specified time. Note that the TTL concerns the inserted values, not the column themselves. This means that any subsequent update of the column will also reset the TTL (to whatever TTL is specified in that update). By default, values never expire. A TTL of 0 or a negative one is equivalent to no TTL.</li></ul><h3 id="deleteStmt">DELETE</h3><p><i>Syntax:</i></p><pre class="syntax"><pre><delete-stmt> ::= DELETE ( <selection> ( ',' <selection> )* )? FROM <tablename> ( USING TIMESTAMP <integer>)? WHERE <where-clause> Modified: cassandra/site/publish/doc/cql3/CQL-2.0.html URL: http://svn.apache.org/viewvc/cassandra/site/publish/doc/cql3/CQL-2.0.html?rev=1576002&r1=1576001&r2=1576002&view=diff ============================================================================== --- cassandra/site/publish/doc/cql3/CQL-2.0.html (original) +++ cassandra/site/publish/doc/cql3/CQL-2.0.html Mon Mar 10 17:03:32 2014 @@ -60,9 +60,6 @@ CREATE KEYSPACE Excalibur <column-definition> ::= <identifier> <type> ( STATIC )? ( PRIMARY KEY )? | PRIMARY KEY '(' <partition-key> ( ',' <identifier> )* ')' -<partition-key> ::= <partition-key> - | '(' <partition-key> ( ',' <identifier> )* ')' - <partition-key> ::= <identifier> | '(' <identifier> (',' <identifier> )* ')'