68 lines
2.3 KiB
Markdown
68 lines
2.3 KiB
Markdown
---
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title: 参数绑定写入
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sidebar_label: 参数绑定
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toc_max_heading_level: 4
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---
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import Tabs from "@theme/Tabs";
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import TabItem from "@theme/TabItem";
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通过参数绑定方式写入数据时，能避免SQL语法解析的资源消耗，从而显著提升写入性能。示例代码如下。
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<Tabs defaultValue="java" groupId="stmt">
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<TabItem value="java" label="Java">
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```java
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public class WSParameterBindingBasicDemo {
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// modify host to your own
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private static final String host = "127.0.0.1";
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private static final Random random = new Random(System.currentTimeMillis());
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private static final int numOfSubTable = 10, numOfRow = 10;
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public static void main(String[] args) throws SQLException {
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String jdbcUrl = "jdbc:TAOS-RS://" + host + ":6041/?batchfetch=true";
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Connection conn = DriverManager.getConnection(jdbcUrl, "root", "taosdata");
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init(conn);
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String sql = "INSERT INTO ? USING meters TAGS(?,?) VALUES (?,?,?,?)";
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try (TSWSPreparedStatement pstmt = conn.prepareStatement(sql).unwrap(TSWSPreparedStatement.class)) {
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for (int i = 1; i <= numOfSubTable; i++) {
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// set table name
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pstmt.setTableName("d_bind_" + i);
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// set tags
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pstmt.setTagInt(0, i);
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pstmt.setTagString(1, "location_" + i);
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// set columns
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long current = System.currentTimeMillis();
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for (int j = 0; j < numOfRow; j++) {
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pstmt.setTimestamp(1, new Timestamp(current + j));
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pstmt.setFloat(2, random.nextFloat() * 30);
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pstmt.setInt(3, random.nextInt(300));
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pstmt.setFloat(4, random.nextFloat());
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pstmt.addBatch();
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}
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pstmt.executeBatch();
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}
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}
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conn.close();
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}
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private static void init(Connection conn) throws SQLException {
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try (Statement stmt = conn.createStatement()) {
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stmt.execute("CREATE DATABASE IF NOT EXISTS power");
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stmt.execute("USE power");
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stmt.execute("CREATE STABLE IF NOT EXISTS meters (ts TIMESTAMP, current FLOAT, voltage INT, phase FLOAT) TAGS (groupId INT, location BINARY(24))");
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}
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}
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}
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```
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</TabItem>
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</Tabs> |