private Insert parseInsert() {
Insert command = new Insert(session);
currentPrepared = command;
read("INTO");
Table table = readTableOrView();
command.setTable(table);
Column[] columns = null;
if (readIf("(")) {
if (isSelect()) {
command.setQuery(parseSelect());
read(")");
return command;
}
columns = parseColumnList(table);
command.setColumns(columns);
}
if (readIf("DIRECT")) {
command.setInsertFromSelect(true);
}
if (readIf("SORTED")) {
command.setSortedInsertMode(true);
}
if (readIf("DEFAULT")) { //比如: INSERT INTO tableName DEFAULT VALUES，插入一行默认值
read("VALUES");
Expression[] expr = { };
command.addRow(expr);
} else if (readIf("VALUES")) {
read("(");
do {
ArrayList<Expression> values = New.arrayList();
//比如: "INSERT INTO t VALUES(DEFAULT),('abc'),('123')"，可以同时insert多行
if (!readIf(")")) {
do {
if (readIf("DEFAULT")) {
values.add(null);
} else {
values.add(readExpression());
}
} while (readIfMore());
}
command.addRow(values.toArray(new Expression[values.size()]));
// the following condition will allow (..),; and (..);
} while (readIf(",") && readIf("("));
} else if (readIf("SET")) {
if (columns != null) { //比如INSERT INTO t(name) set name='xyz'，不能同时指定字段列表
throw getSyntaxError();
}
ArrayList<Column> columnList = New.arrayList();
ArrayList<Expression> values = New.arrayList();
do {
//支持INSERT INTO t set name='xyz', f2=DEFAULT，...这样的语法，
columnList.add(parseColumn(table));
read("=");
Expression expression;
if (readIf("DEFAULT")) {
expression = ValueExpression.getDefault();
} else {
expression = readExpression();
}
values.add(expression);
} while (readIf(","));
command.setColumns(columnList.toArray(new Column[columnList.size()]));
command.addRow(values.toArray(new Expression[values.size()]));
} else {
command.setQuery(parseSelect());
}
return command;
}