Neo4j Cypher查询语言详解

参数

Cypher支持带参数的查询。这允许开发者不需要必须构建一个string的查询，并且使得Cypher的查询计划的缓存更容易。

参数可以在where子句，start子句的索引key或索引值，索引查询中作为节点/关系id的引用。

以下是几个在java中使用参数的示例：

节点id参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "id", 0 );

ExecutionResult result = engine.execute( "start n=node({id}) return n.name", params );

节点对象参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "node", andreasNode );

ExecutionResult result = engine.execute( "start n=node({node}) return n.name", params );

多节点id参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "id", Arrays.asList( 0, 1, 2 ) );

ExecutionResult result = engine.execute( "start n=node({id}) return n.name", params );

字符串参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "name", "Johan" );

ExecutionResult result = engine.execute( "start n=node(0,1,2) where n.name = {name} return n", params );

索引键值参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "key", "name" );

params.put( "value", "Michaela" );

ExecutionResult result = engine.execute( "start n=node:people({key} = {value}) return n", params );

索引查询参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "query", "name:Andreas" );

ExecutionResult result = engine.execute( "start n=node:people({query}) return n", params );

• SKIP 与LIMIT * 的数字参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "s", 1 );

params.put( "l", 1 );

ExecutionResult result = engine.execute( "start n=node(0,1,2) return n.name skip {s} limit {l}", params );

• 正则表达式参数

Map<String, Object> params = new HashMap<String, Object>();

params.put( "regex", ".*h.*" );

ExecutionResult result = engine.execute( "start n=node(0,1,2) where n.name =~ {regex} return n.name", params );