Schema synchronization improvements

Author: ZorTik

api/src/main/java/me/zort/sqllib/api/model/TableSchema.java

@@ -1,7 +1,5 @@
 package me.zort.sqllib.api.model;
 
-import me.zort.sqllib.util.Pair;
-
 public class TableSchema {
 
     private final String table;

api/src/main/java/me/zort/sqllib/internal/annotation/Default.java

@@ -0,0 +1,12 @@
+package me.zort.sqllib.internal.annotation;
+
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target(ElementType.FIELD)
+public @interface Default {
+    String value();
+}

core/src/main/java/me/zort/sqllib/model/DatabaseSchemaBuilder.java

@@ -4,11 +4,10 @@
 import me.zort.sqllib.api.model.TableSchema;
 import me.zort.sqllib.api.model.TableSchemaBuilder;
 
-import java.sql.PreparedStatement;
-import java.sql.ResultSet;
-import java.sql.ResultSetMetaData;
-import java.sql.SQLException;
+import java.sql.*;
+import java.util.HashMap;
 import java.util.HashSet;
+import java.util.Map;
 import java.util.Set;
 import java.util.function.Function;
 
@@ -31,24 +30,37 @@ public DatabaseSchemaBuilder(Function<String, PreparedStatement> statementFactor
     public TableSchema buildTableSchema() {
         try(PreparedStatement statement = statementFactory.apply("SELECT * FROM " + table + " LIMIT 0;");
             ResultSet rs = statement.executeQuery()) {
-            ResultSetMetaData meta = rs.getMetaData();
-            ResultSet primaryKeysRS = statement.getConnection().getMetaData().getPrimaryKeys(null, null, table);
+            ResultSetMetaData rsMeta = rs.getMetaData();
+            DatabaseMetaData connectionMeta = statement.getConnection().getMetaData();
+            ResultSet primaryKeysRS = connectionMeta.getPrimaryKeys(null, null, table);
+            ResultSet defaultValuesRS = connectionMeta.getColumns(null, null, table, null);
             Set<String> primaryKeys = new HashSet<>();
+            Map<String, String> defaultValues = new HashMap<>();
             while (primaryKeysRS.next()) {
                 primaryKeys.add(primaryKeysRS.getString("COLUMN_NAME").toUpperCase());
             }
+            while (defaultValuesRS.next()) {
+                String defaultValue = defaultValuesRS.getString("COLUMN_DEF");
+                if (defaultValue != null) {
+                    defaultValues.put(defaultValuesRS.getString("COLUMN_NAME").toUpperCase(), defaultValue);
+                }
+            }
             primaryKeysRS.close();
+            defaultValuesRS.close();
 
-            ColumnDefinition[] definitions = new ColumnDefinition[meta.getColumnCount()];
+            ColumnDefinition[] definitions = new ColumnDefinition[rsMeta.getColumnCount()];
             for (int i = 0; i < definitions.length; i++) {
-                String name = meta.getColumnName(i + 1);
-                String type = prepareColumnType(meta.getColumnTypeName(i + 1));
-                if (meta.getColumnClassName(i + 1).equals(String.class.getName()) && meta.getColumnDisplaySize(i + 1) > 0) {
-                    type += "(" + meta.getColumnDisplaySize(i + 1) + ")";
+                String name = rsMeta.getColumnName(i + 1);
+                String type = prepareColumnType(rsMeta.getColumnTypeName(i + 1));
+                if (rsMeta.getColumnClassName(i + 1).equals(String.class.getName()) && rsMeta.getColumnDisplaySize(i + 1) > 0) {
+                    type += "(" + rsMeta.getColumnDisplaySize(i + 1) + ")";
                 }
-                if (primaryKeys.contains(meta.getColumnName(i + 1).toUpperCase())) {
+                if (primaryKeys.contains(name.toUpperCase())) {
                     type += " PRIMARY KEY";
                 }
+                if (defaultValues.containsKey(name.toUpperCase())) {
+                    type += " DEFAULT " + defaultValues.get(name.toUpperCase());
+                }
                 definitions[i] = new ColumnDefinition(name, type);
             }
             return new TableSchema(table, definitions);

core/src/main/java/me/zort/sqllib/model/EntitySchemaBuilder.java

@@ -7,6 +7,7 @@
 import me.zort.sqllib.api.model.TableSchema;
 import me.zort.sqllib.api.model.TableSchemaBuilder;
 import me.zort.sqllib.api.options.NamingStrategy;
+import me.zort.sqllib.internal.annotation.Default;
 import me.zort.sqllib.internal.annotation.JsonField;
 import me.zort.sqllib.internal.annotation.NullableField;
 import me.zort.sqllib.internal.annotation.PrimaryKey;
@@ -66,6 +67,13 @@ public TableSchema buildTableSchema() {
                     colType += " NOT NULL";
                 }
             }
+            if (colType != null && field.isAnnotationPresent(Default.class)) {
+                String defaultValue = field.getAnnotation(Default.class).value();
+                if ((field.getType().equals(String.class) || field.isAnnotationPresent(JsonField.class))
+                        && !(defaultValue.startsWith("'") && defaultValue.endsWith("'")))
+                    defaultValue = "'" + defaultValue + "'";
+                colType += " DEFAULT " + defaultValue;
+            }
 
             defs = Arrays.add(defs, new ColumnDefinition(colName, colType));