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TDengine
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update parameter-binding doc 

update parameter-binding doc
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documentation20/cn/08.connector/01.java/docs.md
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...@@ -331,49 +331,238 @@ JDBC连接器可能报错的错误码包括3种：JDBC driver本身的报错（ ...@@ -331,49 +331,238 @@ JDBC连接器可能报错的错误码包括3种：JDBC driver本身的报错（
### <a class="anchor" id="stmt-java"></a>通过参数绑定写入数据 ### <a class="anchor" id="stmt-java"></a>通过参数绑定写入数据
从 2.1.2.0 版本开始，TDengine 的 **JDBC-JNI** 实现大幅改进了参数绑定方式对数据写入（INSERT）场景的支持。采用这种方式写入数据时，能避免 SQL 语法解析的资源消耗，从而在很多情况下显著提升写入性能。（注意：**JDBC-RESTful** 实现并不提供参数绑定这种使用方式。） 从 2.1.2.0 版本开始，TDengine 的 JDBC-JNI 实现大幅改进了参数绑定方式对数据写入（INSERT）场景的支持。采用这种方式写入数据时，能避免 SQL 语法解析的资源消耗，从而在很多情况下显著提升写入性能。
注意：
* JDBC-RESTful 实现并不提供参数绑定这种使用方式
* 以下示例代码基于taos-jdbcdriver-2.0.36
* binary类型数据需要调用setString方法，nchar类型数据需要调用setNString方法
* setString 和 setNString 都要求用户在 size 参数里声明表定义中对应列的列宽
示例代码：
```java ```java
Random r = new Random(); public class ParameterBindingDemo {
// INSERT 语句中，VALUES 部分允许指定具体的数据列；如果采取自动建表，则 TAGS 部分需要设定全部 TAGS 列的参数值： private static final String host = "127.0.0.1";
TSDBPreparedStatement s = (TSDBPreparedStatement) conn.prepareStatement("insert into ? using weather_test tags (?, ?) (ts, c1, c2) values(?, ?, ?)"); private static final Random random = new Random(System.currentTimeMillis());
private static final int BINARY_COLUMN_SIZE = 20;
// 设定数据表名： private static final String[] schemaList = {
s.setTableName("w1"); "create table stable1(ts timestamp, f1 tinyint, f2 smallint, f3 int, f4 bigint) tags(t1 tinyint, t2 smallint, t3 int, t4 bigint)",
// 设定 TAGS 取值： "create table stable2(ts timestamp, f1 float, f2 double) tags(t1 float, t2 double)",
s.setTagInt(0, r.nextInt(10)); "create table stable3(ts timestamp, f1 bool) tags(t1 bool)",
s.setTagString(1, "Beijing"); "create table stable4(ts timestamp, f1 binary(" + BINARY_COLUMN_SIZE + ")) tags(t1 binary(" + BINARY_COLUMN_SIZE + "))",
"create table stable5(ts timestamp, f1 nchar(" + BINARY_COLUMN_SIZE + ")) tags(t1 nchar(" + BINARY_COLUMN_SIZE + "))"
int numOfRows = 10; };
private static final int numOfSubTable = 10, numOfRow = 10;
// VALUES 部分以逐列的方式进行设置：
ArrayList<Long> ts = new ArrayList<>(); public static void main(String[] args) throws SQLException {
for (int i = 0; i < numOfRows; i++){
ts.add(System.currentTimeMillis() + i); String jdbcUrl = "jdbc:TAOS://" + host + ":6030/";
} Connection conn = DriverManager.getConnection(jdbcUrl, "root", "taosdata");
s.setTimestamp(0, ts);
init(conn);
ArrayList<Integer> s1 = new ArrayList<>();
for (int i = 0; i < numOfRows; i++){ bindInteger(conn);
s1.add(r.nextInt(100));
} bindFloat(conn);
s.setInt(1, s1);
bindBoolean(conn);
ArrayList<String> s2 = new ArrayList<>();
for (int i = 0; i < numOfRows; i++){ bindBytes(conn);
s2.add("test" + r.nextInt(100));
bindString(conn);
conn.close();
}
private static void init(Connection conn) throws SQLException {
try (Statement stmt = conn.createStatement()) {
stmt.execute("drop database if exists test_parabind");
stmt.execute("create database if not exists test_parabind");
stmt.execute("use test_parabind");
for (int i = 0; i < schemaList.length; i++) {
stmt.execute(schemaList[i]);
}
}
}
private static void bindInteger(Connection conn) throws SQLException {
String sql = "insert into ? using stable1 tags(?,?,?,?) values(?,?,?,?,?)";
try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
for (int i = 1; i <= numOfSubTable; i++) {
// set table name
pstmt.setTableName("t1_" + i);
// set tags
pstmt.setTagByte(0, Byte.parseByte(Integer.toString(random.nextInt(Byte.MAX_VALUE))));
pstmt.setTagShort(1, Short.parseShort(Integer.toString(random.nextInt(Short.MAX_VALUE))));
pstmt.setTagInt(2, random.nextInt(Integer.MAX_VALUE));
pstmt.setTagLong(3, random.nextLong());
// set columns
ArrayList<Long> tsList = new ArrayList<>();
long current = System.currentTimeMillis();
for (int j = 0; j < numOfRow; j++)
tsList.add(current + j);
pstmt.setTimestamp(0, tsList);
ArrayList<Byte> f1List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f1List.add(Byte.parseByte(Integer.toString(random.nextInt(Byte.MAX_VALUE))));
pstmt.setByte(1, f1List);
ArrayList<Short> f2List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f2List.add(Short.parseShort(Integer.toString(random.nextInt(Short.MAX_VALUE))));
pstmt.setShort(2, f2List);
ArrayList<Integer> f3List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f3List.add(random.nextInt(Integer.MAX_VALUE));
pstmt.setInt(3, f3List);
ArrayList<Long> f4List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f4List.add(random.nextLong());
pstmt.setLong(4, f4List);
// add column
pstmt.columnDataAddBatch();
}
// execute column
pstmt.columnDataExecuteBatch();
}
}
private static void bindFloat(Connection conn) throws SQLException {
String sql = "insert into ? using stable2 tags(?,?) values(?,?,?)";
TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class);
for (int i = 1; i <= numOfSubTable; i++) {
// set table name
pstmt.setTableName("t2_" + i);
// set tags
pstmt.setTagFloat(0, random.nextFloat());
pstmt.setTagDouble(1, random.nextDouble());
// set columns
ArrayList<Long> tsList = new ArrayList<>();
long current = System.currentTimeMillis();
for (int j = 0; j < numOfRow; j++)
tsList.add(current + j);
pstmt.setTimestamp(0, tsList);
ArrayList<Float> f1List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f1List.add(random.nextFloat());
pstmt.setFloat(1, f1List);
ArrayList<Double> f2List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f2List.add(random.nextDouble());
pstmt.setDouble(2, f2List);
// add column
pstmt.columnDataAddBatch();
}
// execute
pstmt.columnDataExecuteBatch();
// close if no try-with-catch statement is used
pstmt.close();
}
private static void bindBoolean(Connection conn) throws SQLException {
String sql = "insert into ? using stable3 tags(?) values(?,?)";
try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
for (int i = 1; i <= numOfSubTable; i++) {
// set table name
pstmt.setTableName("t3_" + i);
// set tags
pstmt.setTagBoolean(0, random.nextBoolean());
// set columns
ArrayList<Long> tsList = new ArrayList<>();
long current = System.currentTimeMillis();
for (int j = 0; j < numOfRow; j++)
tsList.add(current + j);
pstmt.setTimestamp(0, tsList);
ArrayList<Boolean> f1List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++)
f1List.add(random.nextBoolean());
pstmt.setBoolean(1, f1List);
// add column
pstmt.columnDataAddBatch();
}
// execute
pstmt.columnDataExecuteBatch();
}
}
private static void bindBytes(Connection conn) throws SQLException {
String sql = "insert into ? using stable4 tags(?) values(?,?)";
try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
for (int i = 1; i <= numOfSubTable; i++) {
// set table name
pstmt.setTableName("t4_" + i);
// set tags
pstmt.setTagString(0, new String("abc"));
// set columns
ArrayList<Long> tsList = new ArrayList<>();
long current = System.currentTimeMillis();
for (int j = 0; j < numOfRow; j++)
tsList.add(current + j);
pstmt.setTimestamp(0, tsList);
ArrayList<String> f1List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++) {
f1List.add(new String("abc"));
}
pstmt.setString(1, f1List, BINARY_COLUMN_SIZE);
// add column
pstmt.columnDataAddBatch();
}
// execute
pstmt.columnDataExecuteBatch();
}
}
private static void bindString(Connection conn) throws SQLException {
String sql = "insert into ? using stable5 tags(?) values(?,?)";
try (TSDBPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSDBPreparedStatement.class)) {
for (int i = 1; i <= numOfSubTable; i++) {
// set table name
pstmt.setTableName("t5_" + i);
// set tags
pstmt.setTagNString(0, "北京-abc");
// set columns
ArrayList<Long> tsList = new ArrayList<>();
long current = System.currentTimeMillis();
for (int j = 0; j < numOfRow; j++)
tsList.add(current + j);
pstmt.setTimestamp(0, tsList);
ArrayList<String> f1List = new ArrayList<>();
for (int j = 0; j < numOfRow; j++) {
f1List.add("北京-abc");
}
pstmt.setNString(1, f1List, BINARY_COLUMN_SIZE);
// add column
pstmt.columnDataAddBatch();
}
// execute
pstmt.columnDataExecuteBatch();
}
}
} }
s.setString(2, s2, 10);
// AddBatch 之后，缓存并未清空。为避免混乱，并不推荐在 ExecuteBatch 之前再次绑定新一批的数据：
s.columnDataAddBatch();
// 执行绑定数据后的语句：
s.columnDataExecuteBatch();
// 执行语句后清空缓存。在清空之后，可以复用当前的对象，绑定新的一批数据（可以是新表名、新 TAGS 值、新 VALUES 值）：
s.columnDataClearBatch();
// 执行完毕，释放资源：
s.columnDataCloseBatch();
``` ```
用于设定 TAGS 取值的方法总共有： 用于设定 TAGS 取值的方法总共有：
...@@ -405,8 +594,6 @@ public void setString(int columnIndex, ArrayList<String> list, int size) throws ...@@ -405,8 +594,6 @@ public void setString(int columnIndex, ArrayList<String> list, int size) throws
public void setNString(int columnIndex, ArrayList<String> list, int size) throws SQLException public void setNString(int columnIndex, ArrayList<String> list, int size) throws SQLException
``` ```
其中 setString 和 setNString 都要求用户在 size 参数里声明表定义中对应列的列宽。
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