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Add query-only mode for piping results to visidata/pspg/less

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Query mode auto-activates when destination flags are omitted, outputting CSV/TSV to stdout for interactive data exploration of DB2 iSeries queries.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
This commit is contained in:
Paul Trowbridge 2026-01-15 00:53:26 -05:00
parent 85355efe8f
commit 6c9b0f96a0
1 changed files with 148 additions and 32 deletions
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118
jrunner/src/main/java/jrunner/jrunner.java
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@ -27,6 +27,8 @@ public class jrunner {
String nr = "";
String nc = "";
String nl = "\n";
Boolean queryMode = false;
String outputFormat = "csv";
String msg = "";
Connection scon = null;
Connection dcon = null;
@ -50,6 +52,7 @@ public class jrunner {
msg = msg + nl + "-dt fully qualified name of destination table";
msg = msg + nl + "-t trim text";
msg = msg + nl + "-c clear target table";
msg = msg + nl + "-f output format (csv, tsv, table, json) - default: csv";
msg = msg + nl + "--help info";
//---------------------------------------parse args into variables-------------------------------------------------
@ -104,6 +107,9 @@ public class jrunner {
case "-c":
clear = true;
break;
case "-f":
outputFormat = args[i+1].toLowerCase();
break;
case "-v":
System.out.println(msg);
return;
@ -127,6 +133,15 @@ public class jrunner {
}
}
// Detect query mode when destination flags are not provided
queryMode = dcu.isEmpty() && dcn.isEmpty() && dcp.isEmpty() && dt.isEmpty();
if (queryMode) {
System.err.println("------------query mode------------------------------------");
System.err.println("source db uri: " + scu);
System.err.println("source db username: " + scn);
System.err.println("output format: " + outputFormat);
} else {
System.out.println("------------db info---------------------------------------");
System.out.println("source db uri: " + scu);
System.out.println("source db username: " + scn);
@ -136,6 +151,7 @@ public class jrunner {
System.out.println(sq);
System.out.println("------------destination table-----------------------------");
System.out.println(dt);
}
//return;
@ -149,7 +165,11 @@ public class jrunner {
//-------------------------------------------establish connections-------------------------------------------------
//source database
if (queryMode) {
System.err.println("------------open database connection---------------------");
} else {
System.out.println("------------open database connections---------------------");
}
try {
scon = DriverManager.getConnection(scu, scn, scp);
} catch (SQLException e) {
@ -159,6 +179,7 @@ public class jrunner {
}
System.out.println(" ✅ source database");
//destination database
if (!queryMode) {
try {
dcon = DriverManager.getConnection(dcu, dcn, dcp);
} catch (SQLException e) {
@ -167,6 +188,7 @@ public class jrunner {
System.exit(0);
}
System.out.println(" ✅ destination database");
}
//----------------------------------------open resultset------------------------------------------------------------
try {
stmt = scon.createStatement();
@ -204,7 +226,7 @@ public class jrunner {
System.exit(0);
}
//-------------------------clear the target table if requeted----------------------------------------------------
if (clear) {
if (!queryMode && clear) {
System.out.println("------------clear target table----------------------------");
sql = "DELETE FROM " + dt;
try {
@ -217,6 +239,15 @@ public class jrunner {
System.exit(0);
}
}
if (queryMode) {
//-------------------------------output query results--------------------------------------------------------
try {
outputQueryResults(rs, cols, dtn, outputFormat);
} catch (SQLException e) {
e.printStackTrace();
System.exit(0);
}
} else {
System.out.println("------------row count-------------------------------------");
//-------------------------------build & execute sql-------------------------------------------------------------
try {
@ -354,22 +385,107 @@ public class jrunner {
e.printStackTrace();
System.exit(0);
}
}
//System.out.println(sql);
//---------------------------------------close connections--------------------------------------------------------
try {
scon.close();
if (!queryMode && dcon != null) {
dcon.close();
}
} catch (SQLException e) {
System.out.println("issue closing connections");
e.printStackTrace();
}
if (!queryMode) {
System.out.println(" rows written");
tsEnd = Timestamp.from(Instant.now());
System.out.println(tsStart);
System.out.println(tsEnd);
}
//long time = Duration.between(tsStart, tsEnd).toMillis();
//System.out.println("time elapsed: " + time);
System.out.println();
}
private static void outputQueryResults(ResultSet rs, int cols, String[] dtn, String format) throws SQLException {
switch (format) {
case "csv":
outputCSV(rs, cols);
break;
case "tsv":
outputTSV(rs, cols);
break;
case "table":
System.err.println("Table format not yet implemented, defaulting to CSV");
outputCSV(rs, cols);
break;
case "json":
System.err.println("JSON format not yet implemented, defaulting to CSV");
outputCSV(rs, cols);
break;
default:
System.err.println("Unknown format: " + format + ", defaulting to CSV");
outputCSV(rs, cols);
break;
}
}
private static void outputCSV(ResultSet rs, int cols) throws SQLException {
// Print header row
for (int i = 1; i <= cols; i++) {
if (i > 1) System.out.print(",");
System.out.print(escapeCSV(rs.getMetaData().getColumnName(i)));
}
System.out.println();
// Print data rows
while (rs.next()) {
for (int i = 1; i <= cols; i++) {
if (i > 1) System.out.print(",");
String value = rs.getString(i);
if (rs.wasNull() || value == null) {
// Empty field for NULL
} else {
System.out.print(escapeCSV(value));
}
}
System.out.println();
}
}
private static void outputTSV(ResultSet rs, int cols) throws SQLException {
// Print header row
for (int i = 1; i <= cols; i++) {
if (i > 1) System.out.print("\t");
System.out.print(escapeTSV(rs.getMetaData().getColumnName(i)));
}
System.out.println();
// Print data rows
while (rs.next()) {
for (int i = 1; i <= cols; i++) {
if (i > 1) System.out.print("\t");
String value = rs.getString(i);
if (rs.wasNull() || value == null) {
// Empty field for NULL
} else {
System.out.print(escapeTSV(value));
}
}
System.out.println();
}
}
private static String escapeCSV(String value) {
if (value.contains(",") || value.contains("\"") || value.contains("\n") || value.contains("\r")) {
return "\"" + value.replaceAll("\"", "\"\"") + "\"";
}
return value;
}
private static String escapeTSV(String value) {
return value.replaceAll("\t", " ").replaceAll("\n", " ").replaceAll("\r", " ");
}
}